Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
CLARK KEITH E
  2. Issuer Name and Ticker or Trading Symbol
COMPASS MINERALS INTERNATIONAL INC [CMP]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Vice President
(Last)
(First)
(Middle)
COMPASS MINERALS INTERNATIONAL, 9900 WEST 109TH STREET, SUITE 100
3. Date of Earliest Transaction (Month/Day/Year)
03/10/2012
(Street)

OVERLAND PARK, KS 66210
4. If Amendment, Date Original Filed(Month/Day/Year)
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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 03/10/2012   M   2,756 A $ 0 40,723 D  
Common Stock 03/12/2012   S   2,756 D $ 71.88 (1) 37,967 D  
Common Stock               249 (2) I Company 401 (k) Plan

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Restricted Stock Unit $ 0 03/10/2012   M     2,756 03/10/2012 03/10/2012 Common Stock 2,756 (3) 0 D  
Restricted Stock Unit $ 0             03/10/2013 03/10/2013 Common Stock 1,974   1,974 D  
Restricted Stock Unit $ 0             03/10/2014 03/10/2014 Common Stock 1,793   1,793 D  
Restricted Stock Unit $ 0 03/12/2012   A(4)   2,162   03/12/2015 03/12/2015 Common Stock 2,162 $ 0 2,162 D  
Stock Option (Right to Buy) $ 33.44             03/12/2008 03/12/2014 Common Stock 10,000   10,000 D  
Stock Option (Right to Buy) $ 55.12             03/10/2009 03/10/2015 Common Stock 8,071   8,071 D  
Stock Option (Right to Buy) $ 58.99             03/10/2010 03/10/2016 Common Stock 8,453   8,453 D  
Stock Option (Right to Buy) $ 78.51             03/10/2011 03/10/2017 Common Stock 5,524   5,524 D  
Stock Option (Right to Buy) $ 86.47             03/10/2012 03/10/2018 Common Stock 3,748   3,748 D  
Stock Option (Right to Buy) $ 71.69 03/12/2012   A(5)   4,715   03/12/2013 03/12/2019 Common Stock 4,715 $ 0 4,715 D  
Performance Share Unit $ 0             03/10/2013 03/10/2013 Common Stock 509   509 D  
Performance Share Unit $ 0             03/10/2014 03/10/2014 Common Stock 1,172   1,172 D  
Performance Stock Unit (6) $ 0 (7) 03/12/2012   A(6)   1,477   03/12/2015 03/12/2015 Common Stock 1,477 (8) $ 0 1,477 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
CLARK KEITH E
COMPASS MINERALS INTERNATIONAL
9900 WEST 109TH STREET, SUITE 100
OVERLAND PARK, KS 66210
      Vice President  

Signatures

 /s/ Robert E. Marsh as Attorney-in-Fact   03/13/2012
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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 2,756 shares were traded in blocks ranging in price from $71.80 to $71.94. $71.88 is the weighted average price. Information regarding the number of shares sold at each separate price is available upon request by the SEC staff, the issuer, or any security holder of the issuer.
(2) The information in this report is based on a 401(k) plan statement dated as of 03/01/2012.
(3) All Restricted Stock Units have a conversion price of $0.00.
(4) Restricted Stock Units granted: 3 year cliff vest on 3-12-2015.
(5) Stock options granted: vesting 25% after year one and then 25% per year thereafter.
(6) Performance Stock Units are divided into three approximately equal tranches, each having a performance period of one year. On the third anniversary of the grant date, PSUs vest based on achievement of total shareholder return ("TSR") performance goals for each tranche. Payout for vested PSUs ranges from 0% to 150% based on the Company's TSR percentile compared to the TSR of the companies comprising a market index. TSR is measured generally as the increase or decrease in the market value of Company common stock including the reinvestment of dividends. If a participant terminates employment prior to the third anniversary of the grant date, the PSUs will be forfeited except in the case of death or disability. If a change of control occurs before the third anniversary of the grant date, PSUs not previously forfeited will vest and be distributed immediately. Dividend equivalents are paid on PSUs earned in a year, subject to restrictions. PSUs have no voting rights.
(7) All Performance Stock Units have a conversion price of $0.00.
(8) The grant amount of 1,477 PSUs assumes 100% vesting. Since payout for PSUs can range from 0% to 150%, the maximum number of shares that could be earned and vest at the end of the three-year vesting period is 2,216.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.