<PAGE>   1
      As filed with the Securities and Exchange Commission on October 31, 1997.

                                                          Registration No. 333-

===============================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               ----------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               ----------------

                                 CMP MEDIA INC.
             (Exact name of registrant as specified in its charter)

                 DELAWARE                                   11-2240940     
       (State or other jurisdiction                      (I.R.S. Employer  
     of incorporation or organization)                  Identification No.)
 
            600 COMMUNITY DRIVE                               11030     
            MANHASSET, NEW YORK                             (Zip Code)   
 (Address of Principal Executive Offices)                     

                                ----------------

                  CMP MEDIA INC. EMPLOYEE STOCK PURCHASE PLAN
                              (Full title of plan)

                               ----------------
                           ROBERT D. MARAFIOTI, ESQ.
                 Vice President, Secretary and General Counsel
                                 CMP Media Inc.
                              600 Community Drive
                           Manhasset, New York 11030
                    (Name and Address of agent for service)

                                ----------------

                     Telephone number of agent for service:
                                 (516) 562-5000

                                ----------------
                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
========================================================================================================================
                                                       Proposed                Proposed
                                                   maximum offering             maximum
  Title of security         Amount being              price per           aggregate offering           Amount of
   being registered          registered*               share**                   price             registration fee
------------------------------------------------------------------------------------------------------------------------
<S>                           <C>                       <C>                   <C>                       <C>   
       Class A
    Common Stock,
    $.01 Par Value            1,500,000                 $16.19                $24,285,000               $7,360
      Per Share
========================================================================================================================
</TABLE>

* In addition, pursuant to Rule 416 under the Securities Act of 1933, this
registration statement also covers an indeterminate number of additional shares
which may be offered and issued in accordance with the Plan terms to prevent
dilution from stock splits, stock dividends or similar transactions, as well as
an indeterminate amount of interests to be offered or sold pursuant to the
employee benefit plan described herein.

** The maximum offering price per share is calculated pursuant to Rule 457(c)
and (h) using the average high and low prices of the security as of October 28,
1997 as reported in NASDAQ.

===============================================================================
<PAGE>   2



                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         CMP Media Inc. (the "Company") hereby incorporates, or will be deemed
to have incorporated, herein by reference the following documents:

         (1) The Company's Prospectus filed pursuant to Rule 424(b) of the
Securities Act for the fiscal year ended December 31, 1996.

         (2) The Company's Form 10-Q for the period ended June 30, 1997.

         (3) The description of the Company's Class A Common Stock contained in
the Company's most recent Securities Exchange Act of 1934 registration
statement, including any amendment thereto or report filed for the purpose of
updating such description.

         (4) All documents filed by the Company pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Securities Exchange Act of 1934 subsequent to the
date of this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered have been sold or which
deregisters all securities then remaining unsold.

ITEM 4.  DESCRIPTION OF SECURITIES

Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

None.

ITEM 6.  INDEMNIFICATION OF OFFICERS AND DIRECTORS

         Section 102(b)(7) of the General Corporation Law of the State of
Delaware (the "DGCL"), provides that a corporation (in its original certificate
of incorporation or an amendment thereto) may eliminate or limit the personal
liability of a director (or certain persons who, pursuant to the provisions of
the certificate of incorporation, exercise or perform duties conferred or
imposed upon directors by the DGCL) to the corporation or its stockholders for
monetary damages for breach of fiduciary duty as a director, provided that such
provisions shall not eliminate or limit the liability of a director (i) for any
breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the DGCL (providing for liability of directors for unlawful payment of
dividends or unlawful stock purchases or redemptions) or (iv) for any
transaction from which the director derived an improper personal benefit.
Section 7.5 of the Certificate of Incorporation of the Company, as amended (the
"Certificate of Incorporation"), limits the liability of directors thereof to
the extent permitted by Section 102(b)(7) of the DGCL.

         Under Section 145 of the DGCL, in general, a corporation may indemnify
its directors, officers, employees or agents against expenses (including
attorney's fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by them in connection with any action, suit or proceeding
brought by third parties to which they may be made parties by reason of their
being or having been directors, officers, employees or agents and shall so
indemnify such persons only if they acted in good faith and in a manner they
reasonably believed to be in or not opposed to the best interests of the
corporation and, with respect to any criminal action or proceeding, had no

<PAGE>   3



reasonable cause to believe their conduct was unlawful. Section 7.4 of the
Certificate of Incorporation gives the Company the power to indemnify its
officers, directors, employees and agents to the full extent permitted by
Delaware law.

         In addition, the CMP Media Inc. Employee Stock Purchase Plan (the
"Plan") provides for the indemnification of officers and directors who serve on
the Plan's administrative committee and for indemnification of any employee,
officer or director who is allocated or delegated responsibility for
administering or interpreting the Plan against any loss, liability, claim, cost
or expense incurred by or asserted against such employee, officer or director
as a result of any act or omission to act in connection with the Plan, unless
arising out of such employee's, officer's or director's fraud or bad faith.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

Not Applicable.

ITEM 8.  EXHIBITS

<TABLE>
<S>               <C>                                                    
 *3.3             Restated Certificate of Incorporation of the Company

 *3.4             Amended and Restated Bylaws of the Company

 *4.1             Reference is made to Exhibits 3.3 and 3.4

 *4.2             Specimen Class A Common Stock certificate

 *4.3             1997 Stockholders' Agreement

  5               Opinion of Dow, Lohnes & Albertson, PLLC

*10.17            CMP Media Inc. Employee Stock Purchase Plan

 23.1             Consent of Coopers & Lybrand

 23.2             Consent of Dow, Lohnes & Albertson
                  (contained in their opinion in Exhibit 5)
</TABLE>

* Incorporated by reference to the corresponding exhibit of the Company's
Registration Statement on Form S-1 (File No. 333-26741)


ITEM 9.  UNDERTAKINGS

         (a)      The undersigned Registrant hereby undertakes:

                  (1)  to file, during any period in which offers or sales are
         being made, a post-effective amendment to this registration statement
         to include any material information with respect to the plan of
         distribution not previously disclosed in the registration statement or
         any material change to such information in the registration statement;

                  (2)  that, for the purpose of determining any liability under
         the Securities Act, each such post effective amendment shall be deemed
         to be a new registration statement relating to the securities offered
         therein, and the offering of such securities at that time shall be
         deemed to be the initial bona fide offering thereof; and

                  (3)  to remove from registration by means of a post-effective
         amendment any of the securities being registered which remain unsold
         at the termination of the offering.

<PAGE>   4

         (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's Annual Report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
Annual Report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the registration statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions or otherwise, the
registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.

<PAGE>   5


                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized in Manhasset, New York on the 31 day of October, 1997.


                         CMP MEDIA INC.                                         
                                                                                
                                                                                
                         By: /s/ Michael S. Leeds                               
                               -------------------------------------------------
                                                Michael S. Leeds                
                               President, Chief Executive Officer and a Director
                         
         Pursuant to the requirements of the Securities Act of 1933, the Plan
Administrators have duly caused this Registration Statement to be signed by the
following persons in the capacities and on the dates indicated.

<TABLE>
<CAPTION>
                               Signature                                  Capacity                                 Date
                               ---------                                  --------                                 ----
<S>                                                        <C>                                     <C>
 /s/ Michael S. Leeds                                                    President,                         October 31, 1997
--------------------------------------------------------           Chief Executive Officer                          
                  Michael S. Leeds                                      and a Director        
                                                                (Principal Executive Officer)

 /s/ Kenneth D. Cron                                              Executive Vice President,                 October 31, 1997
--------------------------------------------------------           President of Publishing                          
                  Kenneth D. Cron                                      and a Director      
                                                               
 /s/ Joseph E. Sichler                                               Vice President and                     October 31, 1997
--------------------------------------------------------            Chief Financial Officer                         
                 Joseph E. Sichler                              (Principal Financial Officer  
                                                                  and Principal Accounting    
                                                                          Officer)            

 /s/ Gerard G. Leeds                                              Director, Co-Chairperson                  October 31, 1997
--------------------------------------------------------            of Board of Directors                           
                    Gerard G. Leeds                            

 /s/ Lilo J. Leeds                                                Director, Co-Chairperson                  October 30, 1997
--------------------------------------------------------           of Board of Directors                            
                    Lilo J. Leeds                                             
</TABLE>

<PAGE>   6


<TABLE>
<S>           /s/ Richard A. Leeds                         <C>                              <C>
--------------------------------------------------------         Director                   October 31, 1997
                 Richard A. Leeds                                                                   
</TABLE>
[{"type": "S-8", "sequence": "1", "description": "CMP MEDIA INC. FORM S-8", "secsgml_size_bytes": 15618}]
{"company-data": {"conformed-name": "CMP MEDIA INC", "cik": "0001034139", "assigned-sic": "2721", "irs-number": "11224090", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-39261", "film-number": "97706044"}, "business-address": {"street1": "600 COMMUNITY DR", "city": "MANHASSET", "state": "NY", "zip": "11030", "phone": "5165625763"}, "mail-address": {"street1": "600 COMMUNITY DRIVE", "city": "MANHASSET", "state": "NY", "zip": "11030"}}
1
      As filed with the Securities and Exchange Commission on October 31, 1997.

                                                          Registration No. 333-

===============================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               ----------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               ----------------

                                 CMP MEDIA INC.
             (Exact name of registrant as specified in its charter)

                 DELAWARE                                   11-2240940     
       (State or other jurisdiction                      (I.R.S. Employer  
     of incorporation or organization)                  Identification No.)
 
            600 COMMUNITY DRIVE                               11030     
            MANHASSET, NEW YORK                             (Zip Code)   
 (Address of Principal Executive Offices)                     

                                ----------------

                  CMP MEDIA INC. EMPLOYEE STOCK PURCHASE PLAN
                              (Full title of plan)

                               ----------------
                           ROBERT D. MARAFIOTI, ESQ.
                 Vice President, Secretary and General Counsel
                                 CMP Media Inc.
                              600 Community Drive
                           Manhasset, New York 11030
                    (Name and Address of agent for service)

                                ----------------

                     Telephone number of agent for service:
                                 (516) 562-5000

                                ----------------
                        CALCULATION OF REGISTRATION FEE
========================================================================================================================
                                                       Proposed                Proposed
                                                   maximum offering             maximum
  Title of security         Amount being              price per           aggregate offering           Amount of
   being registered          registered*               share**                   price             registration fee
------------------------------------------------------------------------------------------------------------------------
Class A
    Common Stock,
    $.01 Par Value            1,500,000                 $16.19                $24,285,000               $7,360
      Per Share
========================================================================================================================
* In addition, pursuant to Rule 416 under the Securities Act of 1933, this
registration statement also covers an indeterminate number of additional shares
which may be offered and issued in accordance with the Plan terms to prevent
dilution from stock splits, stock dividends or similar transactions, as well as
an indeterminate amount of interests to be offered or sold pursuant to the
employee benefit plan described herein.

** The maximum offering price per share is calculated pursuant to Rule 457(c)
and (h) using the average high and low prices of the security as of October 28,
1997 as reported in NASDAQ.

===============================================================================
2

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         CMP Media Inc. (the "Company") hereby incorporates, or will be deemed
to have incorporated, herein by reference the following documents:

         (1) The Company's Prospectus filed pursuant to Rule 424(b) of the
Securities Act for the fiscal year ended December 31, 1996.

         (2) The Company's Form 10-Q for the period ended June 30, 1997.

         (3) The description of the Company's Class A Common Stock contained in
the Company's most recent Securities Exchange Act of 1934 registration
statement, including any amendment thereto or report filed for the purpose of
updating such description.

         (4) All documents filed by the Company pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Securities Exchange Act of 1934 subsequent to the
date of this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered have been sold or which
deregisters all securities then remaining unsold.

ITEM 4.  DESCRIPTION OF SECURITIES

Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

None.

ITEM 6.  INDEMNIFICATION OF OFFICERS AND DIRECTORS

         Section 102(b)(7) of the General Corporation Law of the State of
Delaware (the "DGCL"), provides that a corporation (in its original certificate
of incorporation or an amendment thereto) may eliminate or limit the personal
liability of a director (or certain persons who, pursuant to the provisions of
the certificate of incorporation, exercise or perform duties conferred or
imposed upon directors by the DGCL) to the corporation or its stockholders for
monetary damages for breach of fiduciary duty as a director, provided that such
provisions shall not eliminate or limit the liability of a director (i) for any
breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the DGCL (providing for liability of directors for unlawful payment of
dividends or unlawful stock purchases or redemptions) or (iv) for any
transaction from which the director derived an improper personal benefit.
Section 7.5 of the Certificate of Incorporation of the Company, as amended (the
"Certificate of Incorporation"), limits the liability of directors thereof to
the extent permitted by Section 102(b)(7) of the DGCL.

         Under Section 145 of the DGCL, in general, a corporation may indemnify
its directors, officers, employees or agents against expenses (including
attorney's fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by them in connection with any action, suit or proceeding
brought by third parties to which they may be made parties by reason of their
being or having been directors, officers, employees or agents and shall so
indemnify such persons only if they acted in good faith and in a manner they
reasonably believed to be in or not opposed to the best interests of the
corporation and, with respect to any criminal action or proceeding, had no
3

reasonable cause to believe their conduct was unlawful. Section 7.4 of the
Certificate of Incorporation gives the Company the power to indemnify its
officers, directors, employees and agents to the full extent permitted by
Delaware law.

         In addition, the CMP Media Inc. Employee Stock Purchase Plan (the
"Plan") provides for the indemnification of officers and directors who serve on
the Plan's administrative committee and for indemnification of any employee,
officer or director who is allocated or delegated responsibility for
administering or interpreting the Plan against any loss, liability, claim, cost
or expense incurred by or asserted against such employee, officer or director
as a result of any act or omission to act in connection with the Plan, unless
arising out of such employee's, officer's or director's fraud or bad faith.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

Not Applicable.

ITEM 8.  EXHIBITS
*3.3             Restated Certificate of Incorporation of the Company

 *3.4             Amended and Restated Bylaws of the Company

 *4.1             Reference is made to Exhibits 3.3 and 3.4

 *4.2             Specimen Class A Common Stock certificate

 *4.3             1997 Stockholders' Agreement

  5               Opinion of Dow, Lohnes & Albertson, PLLC

*10.17            CMP Media Inc. Employee Stock Purchase Plan

 23.1             Consent of Coopers & Lybrand

 23.2             Consent of Dow, Lohnes & Albertson
                  (contained in their opinion in Exhibit 5)
* Incorporated by reference to the corresponding exhibit of the Company's
Registration Statement on Form S-1 (File No. 333-26741)

ITEM 9.  UNDERTAKINGS

         (a)      The undersigned Registrant hereby undertakes:

                  (1)  to file, during any period in which offers or sales are
         being made, a post-effective amendment to this registration statement
         to include any material information with respect to the plan of
         distribution not previously disclosed in the registration statement or
         any material change to such information in the registration statement;

                  (2)  that, for the purpose of determining any liability under
         the Securities Act, each such post effective amendment shall be deemed
         to be a new registration statement relating to the securities offered
         therein, and the offering of such securities at that time shall be
         deemed to be the initial bona fide offering thereof; and

                  (3)  to remove from registration by means of a post-effective
         amendment any of the securities being registered which remain unsold
         at the termination of the offering.
4

         (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's Annual Report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
Annual Report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the registration statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions or otherwise, the
registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Act and is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.
5

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized in Manhasset, New York on the 31 day of October, 1997.

                         CMP MEDIA INC.                                         
                                                                                
                                                                                
                         By: /s/ Michael S. Leeds                               
                               -------------------------------------------------
                                                Michael S. Leeds                
                               President, Chief Executive Officer and a Director
                         
         Pursuant to the requirements of the Securities Act of 1933, the Plan
Administrators have duly caused this Registration Statement to be signed by the
following persons in the capacities and on the dates indicated.
Signature                                  Capacity                                 Date
                               ---------                                  --------                                 ----
/s/ Michael S. Leeds                                                    President,                         October 31, 1997
--------------------------------------------------------           Chief Executive Officer                          
                  Michael S. Leeds                                      and a Director        
                                                                (Principal Executive Officer)

 /s/ Kenneth D. Cron                                              Executive Vice President,                 October 31, 1997
--------------------------------------------------------           President of Publishing                          
                  Kenneth D. Cron                                      and a Director      
                                                               
 /s/ Joseph E. Sichler                                               Vice President and                     October 31, 1997
--------------------------------------------------------            Chief Financial Officer                         
                 Joseph E. Sichler                              (Principal Financial Officer  
                                                                  and Principal Accounting    
                                                                          Officer)            

 /s/ Gerard G. Leeds                                              Director, Co-Chairperson                  October 31, 1997
--------------------------------------------------------            of Board of Directors                           
                    Gerard G. Leeds                            

 /s/ Lilo J. Leeds                                                Director, Co-Chairperson                  October 30, 1997
--------------------------------------------------------           of Board of Directors                            
                    Lilo J. Leeds
6
/s/ Richard A. Leeds
--------------------------------------------------------         Director                   October 31, 1997
                 Richard A. Leeds