UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No._)* ATLAS RESOURCE PARTNERS LP ----------------------------------------------------------- (Name of Issuer) Common units representing limited partner units ----------------------------------------------------------- (Title of Class of Securities) 04941A101 ----------------------------------------------------------- (CUSIP Number) December 31, 2012 ----------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [_] Rule 13d-1(b) [X] Rule 13d-1(c) [_] Rule 13d-1(d) ---------------- * 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). 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. CUSIP No. 04941A101 ---------- 1. Names of Reporting Persons/ I.R.S. Identification Nos. of Above Persons (Entities only): LEON G. COOPERMAN ------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) [_] (b) [X] ------------------------------------------------------------------------- 3. SEC Use Only ------------------------------------------------------------------------- 4. Citizenship or Place of Organization: UNITED STATES ------------------------------------------------------------------------- Number of 5. Sole Voting Power: 1,583,229 Shares Bene- ficially 6. Shared Voting Power: 1,294,507 Owned by Each Report- 7. Sole Dispositive Power: 1,583,229 ing Person With 8. Shared Dispositive Power: 1,294,507 ------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 2,877,736 ------------------------------------------------------------------------- 10. Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares [_] ------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (9): 7.2% ------------------------------------------------------------------------- 12. Type of Reporting Person: IN ------------------------------------------------------------------------- 2 CUSIP No. 04941A101 ---------- Item 1(a) Name of Issuer: ATLAS RESOURCE PARTNERS LP (the "Issuer"). Item 1(b) Address of the Issuer's Principal Executive Offices: Park Place Corporate Center One 1000 Commerce Drive, 4th Floor Pittsburgh, PA 15275 Item 2(a) Name of Person Filing: This statement is filed on behalf of Leon G. Cooperman ("Mr. Cooperman"). Mr. Cooperman is, among other activities, an investor engaged in investing for his own account. Mr. Cooperman is the Managing Member of Omega Associates, L.L.C.("Associates"), a limited liability company organized under the laws of the State of Delaware. Associates is a private investment firm formed to invest in and act as general partner of investment partnerships or similar investment vehicles. Associates is the general partner of limited partnerships organized under the laws of Delaware known as Omega Capital Partners, L.P. ("Capital LP"),Omega Capital Investors, L.P.("Investors LP"), and Omega Equity Investors, L.P. ("Equity LP"), and also the general partner of Omega Charitable Partnership L.P. ("Charitable LP"), an exempted limited partnership registered in the Cayman Islands. These entities are private investment firms engaged in the purchase and sale of securities for investment for their own accounts. Mr. Cooperman is the President, CEO, and majority stockholder of Omega Advisors, Inc. ("Advisors"), a Delaware corporation, engaged in investing for its own account and providing investment management services, and Mr. Cooperman is deemed to control said entity. Advisors serves as the investment manager to Omega Overseas Partners, Ltd. ("Overseas"), a Cayman Island exempted company, with a business address at British American Tower, Third Floor, Jennrett Street, Georgetown, Grand Cayman Island, British West Indies. Mr. Cooperman has investment discretion over portfolio investments of Overseas and is deemed to control such investments. Advisors serves as a discretionary investment advisor to a limited number of institutional clients (the "Managed Accounts"). As to the Shares owned by the Managed Accounts, there would be shared power to dispose or to direct the disposition of such Shares because the owners of the Managed Accounts may be deemed beneficial owners of such Shares pursuant to Rule 13d-3 under the Act as a result of their right to terminate the discretionary account within a period of 60 days. Mr. Cooperman is the ultimate controlling person of Associates, Capital LP, Investors LP, Equity LP, Charitable LP, Overseas, and Advisors. Mr. Cooperman is married to an individual named Toby Cooperman. Mr. Cooperman has an adult son named Michael S. Cooperman. The Michael S. Cooperman WRA Trust (the "WRA Trust"), is an irrevocable trust for the benefit of Michael S. Cooperman. Mr. Cooperman has investment authority over the Michael S. Cooperman and the WRA Trust accounts. 3 CUSIP No. 04941A101 ---------- Item 2(a) Name of Person Filing (cont.): Mr. Cooperman helps manage the investments of JCF Metrowest of NJ ("JCF") a charitable organization,and JCF is the sponsoring organization of the Cooperman Family Fund for a Jewish Future ("Cooperman Family Fund"), a Type 1 charitable supporting foundation. Mr. Cooperman is one of the Trustees of the Cooperman Family Fund. Item 2(b) Address of Principal Business Office or, if None, Residence: The address of the principal business office of Mr. Cooperman and the Foundation is 2700 No. Military Trail, Suite 230, Boca Raton FL 33431 Item 2(c) Citizenship: Mr. Cooperman is a United States citizen; Item 2(d) Title of Class of Securities: Common units representing limited partner units (the "Shares") Item 2(e) CUSIP Number: 04941A101 Item 3. If this statement is filed pursuant to Sections 240.13d-1(b) or 240.13d-2(b) or (c): This Item 3 is not applicable. Item 4. Ownership: Item 4(a)(b) Amount Beneficially Owned and Percent of Class: Mr. Cooperman may be deemed the beneficial owner of 2,877,736 Shares which constitutes approximately 7.2 % of the total number of Shares outstanding. This is based on a total of 39,911,497 Shares outstanding as reported on the Company's Form 10-Q filed with the SEC for the quarter ended September 30, 2012. This consists of 694,097 Shares owned by Capital LP; 181,264 Shares owned by Investors LP; 274,988 Shares owned by Equity LP; 18,380 Shares owned by Charitable LP; 250,000 Shares owned by Mr. Cooperman; 50,000 Shares owned by Toby Cooperman; 50,000 Shares owned by Michael S. Cooperman; and 50,000 Shares owned by the WRA Trust; 4,500 owned by Cooperman Family Fund; 10,000 shares owned by JCF; and 1,294,507 owned by Managed Accounts. Item 4(c) Number of Shares as to which such person has: (i) Sole power to vote or to direct the vote: 1,583,229 (ii) Shared power to vote or to direct the vote: 1,294,507 (iii) Sole power to dispose or to direct the disposition of: 1,583,229 (iv) Shared power to dispose or to direct the disposition of: 1,294,507 Item 5. Ownership of Five Percent or Less of a Class: This Item 5 is not applicable. 4 CUSIP No. 04941A101 ---------- Item 6. Ownership of More than Five Percent on Behalf of Another Person: This Item 6 is not applicable. Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company: This Item 7 is not applicable. Item 8. Identification and Classification of Members of the Group: This Item 8 is not applicable. Item 9. Notice of Dissolution of Group: This Item 9 is not applicable. Item 10. Certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the Issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having such purpose or effect. SIGNATURE 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. DATED: February 7, 2013 as of December 31, 2012 LEON G. COOPERMAN By /s/ ALAN M. STARK ------------------ Alan M. Stark Attorney-in-Fact Power of Attorney on file ATTENTION: INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACT CONSTITUTE FEDERAL CRIMINAL VIOLATIONS (SEE 18 U.S.C. 1001). 5