Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  OKeefe Thomas J
 2. Date of Event Requiring Statement (Month/Day/Year)
04/28/2011		 3. Issuer Name and Ticker or Trading Symbol
OLIN CORP [OLN]
(Last)
(First)
(Middle)
OLIN CORPORATION, 600 POWDER MILL ROAD		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President, Winchester
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

EAST ALTON, IL 62024		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock $1 par value 12,719
D
 
Common Stock $1 par value 11,367.7324 (1)
I
By ESOP Trustee

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Employee Stock Option (right to buy) 02/09/2007 02/08/2016 Common Stock 3,925 $ 20.68 D  
Employee Stock Option (right to buy) 02/13/2008 02/12/2017 Common Stock 6,833 $ 16.52 D  
Employee Stock Option (right to buy) 02/07/2009 02/06/2018 Common Stock 7,500 $ 20.29 D  
Employee Stock Option (right to buy) 02/05/2010(2) 02/05/2019 Common Stock 12,500 $ 14.28 D  
Employee Stock Option (right to buy) 02/05/2011(3) 02/04/2020 Common Stock 12,500 $ 15.68 D  
Employee Stock Option (right to buy)   (4) 02/11/2021 Common Stock 14,000 $ 18.78 D  
Restricted Stock Units   (5)   (5) Common Stock 1,667 $ (6) D  
Restricted Stock Units   (7)   (7) Common Stock 1,667 $ (6) D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
OKeefe Thomas J
OLIN CORPORATION
600 POWDER MILL ROAD
EAST ALTON, IL 62024		       President, Winchester  

Signatures

/s/B. M. Pantalone 05/05/2011
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The figure shown represents shares of Olin Common Stock held under the Olin Common Stock Fund of the Olin Corporation Contributing Employee Ownership Plan (CEOP), a tax-conditioned plan reflecting transactions exempt under Rule 16b-3, as reported by the Plan Administrator as of April 28, 2011.
(2) Option vests in three annual installments beginning on 2/5/2010.
(3) Option vests in three annual installments beginning on 2/5/2011.
(4) Option vests in three annual installments beginning on 2/11/2012.
(5) Right to acquire shares of common stock vesting on 2/5/2012.
(6) Security converts on a one-for-one basis.
(7) Right to acquire shares of common stock vesting on 2/5/2013.

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