[SANDELL ASSET MANAGEMENT/CASTLERIGG INVESTMENTS STATIONERY]

March 16, 2005

VIA TELEFAX (916) 351-8668
Board of Directors
GenCorp Inc.
P.O. Box 537012
Sacramento, CA 95853-7012

Attention:
Mr. Terry L. Hall
Chairman of the Board

Re: GenCorp Inc.

Dear Sirs:

     Sandell Asset Management Corp. ("Sandell") and the private investment
funds advised by Sandell (collectively with Sandell, the "Sandell Funds")
are the beneficial owners of 3,064,800 shares of common stock of GenCorp
Inc. ("GenCorp" or the "Company") and $4,000,000 of the Company's 5.75%
Convertible Subordinated Notes due 2007 convertible into 200,000 shares of
the Company's common stock, collectively representing approximately 6.0% of
GenCorp's outstanding shares.

     As a shareholder with a significant ownership of GenCorp, we want to
take this opportunity to highlight to you our perspective that GenCorp's
common shares remain significantly undervalued at the present time. We have
a strong conviction in the view that the intrinsic value of the Company
resides predominantly with its extensive and highly valuable 12,700-acre
real estate holdings around the rapidly growing Sacramento, CA region (the
"Sacramento Property"). While our investment thesis was borne out of
extensive and independent analyses, our overall perspective with regards to
the value of the Sacramento Property is not unique and has also been
highlighted repeatedly in recent investment analyst reports, shareholder
filings, industry commentaries and media stories.

     We are deeply dissatisfied with the decision by the Board of Directors
and management to complete its recent offerings of equity and convertible
securities amid shareholder concerns. While we applaud the Company's recent
move to allow a representative of one large shareholder to attend all
meetings of the Board of Directors as a non-voting observer, we feel that
this falls far short of the corporate governance improvement needed at
GenCorp.

     As such, we would like to see GenCorp:

     -    Close on the divestiture of the Fine Chemicals business in an
          expedited fashion;
     -    Unlock the value of the Sacramento Property by separating out the
          assets in a tax efficient manner such as a spin-off, tracking
          stock, or via a real estate partnership;
     -    Eliminate the classification of its Board of Directors;
     -    Require that all directors stand for election annually;
     -    Remove the shareholder rights plan;
     -    Eliminate any supermajority requirements;
     -    Waive the Ohio anti-takeover statute Section 1704;
     -    Allow special meetings to be called by shareholders holding not
          less than 10% of the voting power;and
     -    Allow action by written consent of a majority of shareholders.

     Additionally, GenCorp could take a very positive step by proactively
inviting one to two representatives of its shareholder base to join the
board of GenCorp in a timely fashion.

     GenCorp's Board has, for the most part, ignored the pleadings of its
largest and most vocal shareholder base which we believe is entirely
inappropriate. We will continue to evaluate any and all options with
respect to our investment in GenCorp as we deem appropriate including, but
not limited to, seeking board representation on GenCorp's Board.

     We are available to discuss the issues raised by our letter and will
continue to monitor the progress made by GenCorp in maximizing shareholder
value.

                                                 Very truly yours,

                                                 SANDELL ASSET MANGEMENT CORP.



                                                 ----------------------------
                                                 Name: Thomas Sandell
                                                 Its: Chief Executive Officer