<PAGE>
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549




                                  SCHEDULE 13G




                    Under the Securities Exchange Act of 1934

                                (Amendment No. )*


                           IDEC Pharmaceuticals Corp.
- -------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
- -------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                   449370105
                       --------------------------------------
                                 (CUSIP Number)

Check the following  box if a fee is being paid with this  statement . (A fee is
not required  only if the filing  person:  (1) has a previous  statement on file
reporting  beneficial  ownership  of more  than  five  percent  of the  class of
securities  described  in Item 1;  and (2) has  filed  no  amendment  subsequent
thereto reporting  beneficial  ownership of five percent or less of such class.)
(See Rule 13d-7).

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).




<PAGE>
CUSIP No. 449370105                                          Page 2 of 13 Pages
                                    13G

1        NAME OF REPORTING PERSON
         S.S OR I.R.S IDENTIFICATION NO. OF ABOVE PERSON

                  INVESCO PLC
                  No SS or IRS Identification Number

2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                  (a)  [ ]
                                  (b)  [X]

3        SEC USE ONLY


4        CITIZENSHIP OR PLACE OF ORGANIZATION

                  England

                                            5        SOLE VOTING POWER
NUMBER OF SHARES                                              None
BENEFICIALLY OWNED
BY EACH REPORTING                           6        SHARED VOTING POWER
PERSON WITH                                                   964,400

                                            7        SOLE DISPOSITIVE POWER
                                                              None

                                            8        SHARED DISPOSITIVE POWER
                                                              964,400

9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  964,400

10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
                  5.5%

12       TYPE OF REPORTING PERSON*
                  H.C.

                                *SEE INSTRUCTION BEFORE FILLING OUT





<PAGE>
CUSIP No. 449370105                                         Page 3 of 13 Pages
                                    13G

1        NAME OF REPORTING PERSON
         S.S OR I.R.S IDENTIFICATION NO. OF ABOVE PERSON

                  INVESCO North American Group, Ltd.
                  No SS or IRS Identification Number

2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                   (a)  [ ]
                                   (b)  [X]

3        SEC USE ONLY


4        CITIZENSHIP OR PLACE OF ORGANIZATION

                  England

                                            5        SOLE VOTING POWER
NUMBER OF SHARES                                              None
BENEFICIALLY OWNED
BY EACH REPORTING                           6        SHARED VOTING POWER
PERSON WITH                                                   964,400

                                            7        SOLE DISPOSITIVE POWER
                                                              None

                                            8        SHARED DISPOSITIVE POWER
                                                              964,400

9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  964,400

10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
                  5.5%

12       TYPE OF REPORTING PERSON*
                  H.C.

         *SEE INSTRUCTION BEFORE FILLING OUT





<PAGE>
CUSIP No. 449370105                                         Page 4 of 13 Pages
                                    13G

1        NAME OF REPORTING PERSON
         S.S OR I.R.S IDENTIFICATION NO. OF ABOVE PERSON

                  INVESCO, Inc.
                  IRS Identification Number 58-1995394

2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                   (a)  [ ]
                                   (b)  [X]

3        SEC USE ONLY


4        CITIZENSHIP OR PLACE OF ORGANIZATION

                  State of Delaware

                                            5        SOLE VOTING POWER
NUMBER OF SHARES                                              None
BENEFICIALLY OWNED
BY EACH REPORTING                           6        SHARED VOTING POWER
PERSON WITH                                                   964,400

                                            7        SOLE DISPOSITIVE POWER
                                                              None

                                            8        SHARED DISPOSITIVE POWER
                                                              964,400

9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  964,400

10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
                  5.5%

12       TYPE OF REPORTING PERSON*
                  H.C.

         *SEE INSTRUCTION BEFORE FILLING OUT





<PAGE>
CUSIP No. 449370105                                          Page 5 of 13 Pages
                                    13G

1        NAME OF REPORTING PERSON
         S.S OR I.R.S IDENTIFICATION NO. OF ABOVE PERSON

                  INVESCO North American Holdings, Inc.
                  IRS Identification Number 51-0264787

2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                  (a)  [ ]
                                  (b)  [X]

3        SEC USE ONLY


4        CITIZENSHIP OR PLACE OF ORGANIZATION

                  State of Delaware

                                            5        SOLE VOTING POWER
NUMBER OF SHARES                                              None
BENEFICIALLY OWNED
BY EACH REPORTING                           6        SHARED VOTING POWER
PERSON WITH                                                   964,400

                                            7        SOLE DISPOSITIVE POWER
                                                              None

                                            8        SHARED DISPOSITIVE POWER
                                                              964,400

9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  964,400

10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
                  5.5%

12       TYPE OF REPORTING PERSON*
                  H.C.

         *SEE INSTRUCTION BEFORE FILLING OUT




<PAGE>
CUSIP No. 449370105                                          Page 6 of 13 Pages
                                    13G

1        NAME OF REPORTING PERSON
         S.S OR I.R.S IDENTIFICATION NO. OF ABOVE PERSON

                  INVESCO Funds Group, Inc.
                  IRS Identification Number 84-0235630

2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                   (a)  [ ]
                                   (b)  [X]

3        SEC USE ONLY


4        CITIZENSHIP OR PLACE OF ORGANIZATION

                  State of Delaware

                                            5        SOLE VOTING POWER
NUMBER OF SHARES                                              None
BENEFICIALLY OWNED
BY EACH REPORTING                           6        SHARED VOTING POWER
PERSON WITH                                                   964,400

                                            7        SOLE DISPOSITIVE POWER
                                                              None

                                            8        SHARED DISPOSITIVE POWER
                                                              964,400

9        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  964,400

10       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*


11       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
                  5.5%

12       TYPE OF REPORTING PERSON*
                  H.C.

         *SEE INSTRUCTION BEFORE FILLING OUT





<PAGE>
Schedule 13G                                                 Page 7 of 13 Pages


Item 1 (a)        Name of Issuer:

                           IDEC Pharmaceuticals Corp.

Item 1 (b)        Address of Issuer's Principal Executive Offices:

                           11011 Torreyana Rd.
                           San Diego, CA  92121-1104

Item 2 (a)        Name of Person filing:

                           INVESCO PLC

Item 2 (b)        Address of Principal Office:

                           11 Devonshire Square
                           London EC2M 4YR
                           England

Item 2 (c)        Citizenship:

                           Organized under the laws of England

Item 2 (d)        Title of Class of Securities:

                           Common Stock

Item 2 (e)        Cusip Number:   449370105


Item 3            If this  statement  is filed  pursuant to Rules  13d-1(b) or
                  13d-2(b), check whether the person filing is a:

(a)      ( )      Broker or Dealer registered under Section 15 of the Act.
(b)      ( )      Bank as defined in Section 3(a)(6) of the Act.
(c)      ( )      Insurance Company as defined in Sec. 3(a)(19) of the Act.
(d)      ( )      Investment Company registered under Section 8 of the 
                  Investment Company Act.
(e)      ( )      Investment Adviser registered under Section 203 of the
                  Investment Advisers Act of 1940.
(f)      ( )      Employee Benefit Plan, Pension Fund which is subject to
                  provisions of Employee Retirement Income Security Act of
                  1974 or Endowment Fund; see Sec. 240.13d-1(b)(1)(ii)(F).
(g)      (X)      Parent Holding Company in accordance with Section
                  240.13d-1(b)(ii)(G).  (Note:  see Item 7)
(h)      ( )      Group, in accordance with Section 240.13d-1(b)(1)(ii)(H).





<PAGE>
Schedule 13G                                                 Page 8 of 13 Pages


Item 4            Ownership:

                  *The information in items 1 and 5 through 11 on the cover 
                  pages (pp. 2-5) on Schedule 13G is hereby incorporated by 
                  reference.

                  The  reporting  persons  expressly  declare that the filing of
                  this  statement  on Schedule  13G shall not be construed as an
                  admission  that they are, for the purposes of Section 13(d) or
                  13(g)  of  the  Securities  and  Exchange  Act  of  1934,  the
                  beneficial owners of any securities covered by this statement.

Item 5            Ownership of five percent or less of a class.

                  Not Applicable

Item 6            Ownership of more than five percent on behalf of another 
                  person.

                  The  reporting  persons  hold the  securities  covered by this
                  report  on  behalf  of other  persons  who  have the  right to
                  receive or the power to direct the receipt of dividends  from,
                  or the proceeds from the sale of such securities. The interest
                  of any  such  persons  does  not  exceed  5% of the  class  of
                  securities.

Item 7            Identification and classification of the subsidiaries which 
                  acquired the security being reported on by the Parent Holding 
                  Company:

                   X       INVESCO North American Group, Ltd. - holding
                  ---      company in accordance with Rule 13d-1(b)(ii)(G).
                   X       INVESCO, Inc. - holding company also in
                  ---      accordance with Rule 13d-1(b)(ii)(G).
                   X       INVESCO North American Holdings, Inc. - holding
                  ---      company also in accordance with Rule 13d-1(b)(ii)(G).
                           INVESCO Capital Management, Inc. -
                  ---      investment adviser  registered under Section 203 of 
                           the Investment Advisers Act of 1940.
                   X       INVESCO Funds Group, Inc. - investment adviser
                  ---      registered under Section 203 of the Investment 
                           Advisers Act of 1940.




<PAGE>
Schedule 13G                                                 Page 9 of 13 Pages


                           INVESCO Management & Research -
                  ---      investment adviser registered under Section 203 of 
                           the Investment Advisers Act of 1940.
                           INVESCO Asset Management Limited -
                  ---      investment adviser organized under the laws of 
                           England.

                  Subsidiaries not indicated with (X) have acquired no shares of
                  security being reported on.

Item 8            Identification and Classification of Members of a Group.

                           Not applicable.

Item 9            Notice of Dissolution of Group.

                           Not applicable.





<PAGE>
Schedule 13G                                               Page 10 of 13 Pages


Item 10  Certification:

                  By signing  below, I certify that, to the best of my knowledge
                  and belief, the securities  referred to above were acquired in
                  the ordinary  course of business and were not acquired for the
                  purpose  of  and  do  not  have  the  effect  of  changing  or
                  influencing  the control of the issuer of such  securities and
                  were not acquired in connection  with or as a  participant  in
                  any transaction having such purposes or effect.

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


February 14, 1997
- ---------------------------------
Date


/s/ Michael S. Perman
- ------------------------------------------
Michael S. Perman,
as Company  Secretary for each of INVESCO PLC 
and INVESCO North American Group, Ltd.





<PAGE>
Schedule 13G                                               Page 11 of 13 Pages


Item 10  Certification:

                  By signing  below, I certify that, to the best of my knowledge
                  and belief, the securities  referred to above were acquired in
                  the ordinary  course of business and were not acquired for the
                  purpose  of  and  do  not  have  the  effect  of  changing  or
                  influencing  the control of the issuer of such  securities and
                  were not acquired in connection  with or as a  participant  in
                  any transaction having such purposes or effect.

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

February 14, 1997
- ---------------------------------
Date


/s/ Deborah Lamb
- ---------------------------------------------
Deborah Lamb, Assistant Secretary
INVESCO, Inc.




<PAGE>
Schedule 13G                                                Page 12 of 13 Pages


Item 10  Certification:

                  By signing  below, I certify that, to the best of my knowledge
                  and belief, the securities  referred to above were acquired in
                  the ordinary  course of business and were not acquired for the
                  purpose  of  and  do  not  have  the  effect  of  changing  or
                  influencing  the control of the issuer of such  securities and
                  were not acquired in connection  with or as a  participant  in
                  any transaction having such purposes or effect.

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


February 14, 1997
- ---------------------------------
Date


/s/ Frank Keeler
- ---------------------------------
Frank Keeler, Secretary
INVESCO North American Holdings, Inc.





<PAGE>
Schedule 13G                                                Page 13 of 13 Pages


Item 10  Certification:

                  By signing  below, I certify that, to the best of my knowledge
                  and belief, the securities  referred to above were acquired in
                  the ordinary  course of business and were not acquired for the
                  purpose  of  and  do  not  have  the  effect  of  changing  or
                  influencing  the control of the issuer of such  securities and
                  were not acquired in connection  with or as a  participant  in
                  any transaction having such purposes or effect.

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


February 14, 1997
- ---------------------------------
Date


/s/ Glen A. Payne
- ---------------------------------
Glen A. Payne, Secretary
INVESCO Funds Group, Inc.