<PAGE>
 
                                             Registration Statement No.333-03955


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                        Intermedia Communications Inc.
       -----------------------------------------------------------------
              (Exact name of issuer as specified in its charter)

            Delaware                                  59-29-13586
      ----------------------------           --------------------------
      (State or other jurisdiction                 (I.R.S. Employer
      incorporation or organization)              Identification No.)

                  3625 Queen Palm Drive, Tampa, Florida 33619
      ----------------------------------------------------------------- 
      (Address of Principal Executive Offices)          (Zip Code)

                        Intermedia Communications Inc.
                           Long-Term Incentive Plan
      ------------------------------------------------------------------
                           (Full title of the plan)

                                David C. Ruberg
                        Chairman of the Board, President
                          and Chief Executive Officer
                         Intermedia Communications Inc.
                             3625 Queen Palm Drive
                             Tampa, Florida 33619 
       -----------------------------------------------------------------
                    (Name and address of agent for service)

                                (813) 829-0011
       -----------------------------------------------------------------
         (Telephone number, including area code, of agent for service)

                                With a copy to:

                    Ralph J. Sutcliffe, Esq.
                    Kronish, Lieb, Weiner & Hellman LLP
                    1114 Avenue of the Americas
                    New York, NY 10036-7798

                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
Title of                                                      Amount         
securities         Amount        Offering        Aggregate    of              
to be              to be         price           offering     registration    
registered         registered    per share(1)    price        fee             
---------------    ----------    ------------    ---------    ------------     
<S>                <C>           <C>             <C>          <C>
 
Common Stock,
$.01 par           1,000,000     $32.1875        $32,187,500  $9,753.78
value
</TABLE>
--------------------------------------------------------------------------------

                                     Page 1

(1)  Average of the bid and asked prices as reported on the Nasdaq National
     Market on July 11, 1997, pursuant to Rule 457(h)(1).
<PAGE>
 
          The contents of the Registration Statement on Form S-8 (File No. 333-
03955) of Intermedia Communications Inc. (f/k/a Intermedia Communications of
Florida, Inc.) are incorporated herein by reference.


Exhibits.
-------- 

 5.1  Opinion of counsel as to legality of the shares of common stock covered 
      by this Registration Statement.                                         
                                                                              
23.1  Consent of independent accountants                                      
                                                                              
23.2  Consent of counsel (included within Exhibit 5.1)                        

                                       2

<PAGE>
 
                                   SIGNATURES

          Pursuant to the requirements of the Securities Act of 1933, as
amended, 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 the City of Tampa, State of Florida, on the 14th day of
July, 1997.

                               Intermedia Communications Inc.           
                               (Registrant)                             
                                                                        
                                                                        
                               By:  /s/  David C. Ruberg                   
                                  ------------------------------------- 
                                  David C. Ruberg                       
                                  Chairman of the Board, President      
                                  and Chief Executive Officer            

          Pursuant to the requirements of the Securities Act of 1933, as
amended, this Registration Statement has been signed below by the following
persons in all capacities and on the dates indicated.

<TABLE>
<CAPTION>
        Signature                 Title                    Date
        ---------                 -----                    ----        
<S>                           <C>                     <C>          

/s/  David C. Ruberg          Chairman of the         July 14, 1997 
-------------------------     Board, President
David C. Ruberg               and Chief Executive  
                              Officer
 
 
/s/  Robert M. Manning        Senior Vice           
-------------------------     President, Chief        July 14, 1997 
Robert M. Manning             Financial Officer                   
                              and Secretary                        
 
 
/s/  Jeanne M. Walters        Controller and          July 14, 1997 
-------------------------     Chief Accounting 
Jeanne M. Walters             Officer                     
 
 
/s/  John C. Baker            Director                July 14, 1997
------------------------- 
John C. Baker

 
/s/  Phillip A. Campbell      Director                July 14, 1997
-------------------------
Philip A. Campbell
 

/s/  George F. Knapp          Director                July 14, 1997
-------------------------
George F. Knapp  
</TABLE>

                                       3
<PAGE>
 
                                 EXHIBIT INDEX
<TABLE>
<CAPTION>
 
Exhibit                                              Page
-------                                              ----
<S>                                                  <C>
 
 5.1  Opinion of counsel as to legality of the   
      shares of common stock covered by this     
      Registration Statement.                    
                                                 
23.1  Consent of independent accountants         
                                                 
23.2  Consent of counsel (included within Exhibit  
      5.1)                                        
 
</TABLE>

                                       4
[{"type": "S-8", "sequence": "1", "description": "LONG-TERM INCENTIVE PLAN", "secsgml_size_bytes": 7187}]
{"company-data": {"conformed-name": "INTERMEDIA COMMUNICATIONS OF FLORIDA INC", "cik": "0000885067", "assigned-sic": "4813", "irs-number": "592913586", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-31367", "film-number": "97641312"}, "business-address": {"street1": "3625 QUEEN PALM DR", "street2": "STE 720", "city": "TAMPA", "state": "FL", "zip": "33619", "phone": "8136210011"}}
Registration Statement No.333-03955

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                        Intermedia Communications Inc.
       -----------------------------------------------------------------
              (Exact name of issuer as specified in its charter)

            Delaware                                  59-29-13586
      ----------------------------           --------------------------
      (State or other jurisdiction                 (I.R.S. Employer
      incorporation or organization)              Identification No.)

                  3625 Queen Palm Drive, Tampa, Florida 33619
      ----------------------------------------------------------------- 
      (Address of Principal Executive Offices)          (Zip Code)

                        Intermedia Communications Inc.
                           Long-Term Incentive Plan
      ------------------------------------------------------------------
                           (Full title of the plan)

                                David C. Ruberg
                        Chairman of the Board, President
                          and Chief Executive Officer
                         Intermedia Communications Inc.
                             3625 Queen Palm Drive
                             Tampa, Florida 33619 
       -----------------------------------------------------------------
                    (Name and address of agent for service)

                                (813) 829-0011
       -----------------------------------------------------------------
         (Telephone number, including area code, of agent for service)

                                With a copy to:

                    Ralph J. Sutcliffe, Esq.
                    Kronish, Lieb, Weiner & Hellman LLP
                    1114 Avenue of the Americas
                    New York, NY 10036-7798

                        CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------
Title of                                                      Amount         
securities         Amount        Offering        Aggregate    of              
to be              to be         price           offering     registration    
registered         registered    per share(1)    price        fee             
---------------    ----------    ------------    ---------    ------------
Common Stock,
$.01 par           1,000,000     $32.1875        $32,187,500  $9,753.78
value
--------------------------------------------------------------------------------

                                     Page 1

(1)  Average of the bid and asked prices as reported on the Nasdaq National
     Market on July 11, 1997, pursuant to Rule 457(h)(1).
The contents of the Registration Statement on Form S-8 (File No. 333-
03955) of Intermedia Communications Inc. (f/k/a Intermedia Communications of
Florida, Inc.) are incorporated herein by reference.

Exhibits.
-------- 

 5.1  Opinion of counsel as to legality of the shares of common stock covered 
      by this Registration Statement.                                         
                                                                              
23.1  Consent of independent accountants                                      
                                                                              
23.2  Consent of counsel (included within Exhibit 5.1)                        

                                       2
SIGNATURES

          Pursuant to the requirements of the Securities Act of 1933, as
amended, 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 the City of Tampa, State of Florida, on the 14th day of
July, 1997.

                               Intermedia Communications Inc.           
                               (Registrant)                             
                                                                        
                                                                        
                               By:  /s/  David C. Ruberg                   
                                  ------------------------------------- 
                                  David C. Ruberg                       
                                  Chairman of the Board, President      
                                  and Chief Executive Officer            

          Pursuant to the requirements of the Securities Act of 1933, as
amended, this Registration Statement has been signed below by the following
persons in all capacities and on the dates indicated.
Signature                 Title                    Date
        ---------                 -----                    ----
/s/  David C. Ruberg          Chairman of the         July 14, 1997 
-------------------------     Board, President
David C. Ruberg               and Chief Executive  
                              Officer
 
 
/s/  Robert M. Manning        Senior Vice           
-------------------------     President, Chief        July 14, 1997 
Robert M. Manning             Financial Officer                   
                              and Secretary                        
 
 
/s/  Jeanne M. Walters        Controller and          July 14, 1997 
-------------------------     Chief Accounting 
Jeanne M. Walters             Officer                     
 
 
/s/  John C. Baker            Director                July 14, 1997
------------------------- 
John C. Baker

 
/s/  Phillip A. Campbell      Director                July 14, 1997
-------------------------
Philip A. Campbell
 

/s/  George F. Knapp          Director                July 14, 1997
-------------------------
George F. Knapp
3
EXHIBIT INDEX
Exhibit                                              Page
-------                                              ----
5.1  Opinion of counsel as to legality of the   
      shares of common stock covered by this     
      Registration Statement.                    
                                                 
23.1  Consent of independent accountants         
                                                 
23.2  Consent of counsel (included within Exhibit  
      5.1)
4