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| x | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|---|--------------------------------------------------------------------------------------|

| o | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|---|------------------------------------------------------------------------------------------|

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| Delaware                                                      |   | 26-1307173                          |
|---------------------------------------------------------------|--------|-------------------------------------|
| (State or Other Jurisdiction ofIncorporation or Organization) |   | (I.R.S. EmployerIdentification No.) |
|                                                          |   |                                |
| 1301 McKinney, Suite 500, Houston, Texas                      |   | 77010                               |
| (Address of Principal Executive Offices)                      |   | (Zip Code)                          |

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| Large accelerated filer |   | o      |   | Accelerated filer         |   | o |
|-------------------------|--------|--------|--------|---------------------------|--------|---|
|                    |   |   |   |
| Non-accelerated filer   |   | x      |   | Smaller reporting company |   | o |

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|   | 1. | Financial Statements. Reference is made to the Index to Consolidated Financial Statements at Item 8 of this annual report on Form 10-K. |
|--------|----|-----------------------------------------------------------------------------------------------------------------------------------------|

|   | 2. | Financial Statement Schedules. All schedules are omitted because they are not applicable or the required information is shown in the financial statements or the notes to the financial statements. |
|--------|----|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 3. | Exhibits. |
|--------|----|-----------|

| NumberExhibit No. |   | Description                                                                                                                                                                                                                                                                                      |
|-------------------|--------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|              |   |
| 2.1               |   | Agreement and Plan of Conversion between Milagro Mezz, LLC and Milagro Holdings, LLC dated October 8, 2009 (incorporated by reference to Exhibit 2.5 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                        |
|              |   |
| 2.2               |   | Certificate of Conversion of Milagro Mezz, LLC dated October 8, 2009 (incorporated by reference to Exhibit 2.6 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                              |
|              |   |
| 3.1               |   | Certificate of Incorporation of Milagro Mezz, Inc. dated October 8, 2009 (incorporated by reference to Exhibit 3.1 to the Registration Statement on Form S-4 of Milagro Oil &Gas, Inc. filed on October 27, 2011).                                                                           |
|              |   |
| 3.2               |   | Certificate of Amendment to Certificate of Incorporation of Milagro Mezz, Inc. dated January 11, 2010 (incorporated by reference to Exhibit 3.2 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                             |
|              |   |
| 3.3               |   | Certificate of Designation of Milagro Mezz, Inc. dated January 13, 2010 (incorporated by reference to Exhibit 3.3 to the Registration Statement on Form S-4 of Milagro Oil &Gas, Inc. filed on October 27, 2011).                                                                            |
|              |   |
| 3.4               |   | Certificate of Amendment to Certificate of Incorporation of Milagro Mezz, Inc. dated February 24, 2011 (incorporated by reference to Exhibit 3.4 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                            |
|              |   |
| 3.5               |   | Certificate of Amendment to Certificate of Incorporation of Milagro Mezz, Inc. dated May 11, 2011 (incorporated by reference to Exhibit 3.5 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                 |
|              |   |
| 3.6               |   | Bylaws of Milagro Mezz, Inc. dated October 8, 2009 (incorporated by reference to Exhibit 3.6 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                                                |
|              |   |
| 3.7               |   | First Amendment to Bylaws of Milagro Mezz, Inc. dated August 18, 2010 (incorporated by reference to Exhibit 3.7 to the Registration Statement on Form S-4 of Milagro Oil &Gas, Inc. filed on October 27, 2011).                                                                              |
|              |   |
| 4.1               |   | Indenture dated as of May 11, 2011 by and among Milagro Oil & Gas, Inc., the guarantors named therein, and Wells Fargo Bank, N.A., as trustee (incorporated by reference to Exhibit 4.1 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011). |
|              |   |
| 4.2               |   | Stockholders’ Agreement of Milagro Mezz, Inc. dated January 13, 2010 (incorporated by reference to Exhibit 4.3 to the Registration Statement on Form S-4 of Milagro Oil &Gas, Inc. filed on October 27, 2011).                                                                         |
|              |   |
| 4.3               |   | First Amendment to Stockholders’ Agreement of Milagro Mezz, Inc. dated August 30, 2010 (incorporated by reference to Exhibit 4.4 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                      |

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| NumberExhibit No. |   | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-------------------|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 10.1              |   | Monitoring Agreement dated as of November 30, 2007 among Milagro Holdings, LLC, Acon Funds Management, L.L.C., Guggenheim Corporate Funding, LLC and West Coast Energy Management Partners LLC (incorporated by reference to Exhibit 10.1 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                                                                                |
|              |   |
| 10.2              |   | Amended and Restated First Lien Credit Agreement dated as of May 11, 2011 among Milagro Exploration, LLC and Milagro Producing, LLC, as borrowers, Milagro Oil & Gas, Inc., as guarantor, Wells Fargo Bank, N.A., as administrative agent, issuer and swing line lender, and the lenders from time to time parties thereto (incorporated by reference to Exhibit 10.2 to the Registration Statement on Form S-4 of Milagro Oil &Gas, Inc. filed on October 27, 2011). |
|              |   |
| 10.3              |   | Employment Agreement of Robert D. LaRocque dated January 1, 2011 (incorporated by reference to Exhibit 10.4 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                                                                                                                                                                                                              |
|              |   |
| 10.4              |   | Employment Agreement of Gary Mabie dated May 14, 2010 (incorporated by reference to Exhibit 10.5 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                                                                                                                                                                                                                         |
|              |   |
| 10.5              |   | Employment Agreement of Marshall L. Munsell dated November 30, 2007 (incorporated by reference to Exhibit 10.6 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                                                                                                                                                                                                           |
|              |   |
| 10.6              |   | Employment Agreement of Thomas C. Langford dated November 30, 2007 (incorporated by reference to Exhibit 10.7 to the Registration Statement on Form S-4 of Milagro Oil & Gas, Inc. filed on October 27, 2011).                                                                                                                                                                                                                                                            |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 10.7              |   | Consulting Agreement among Milagro Oil & Gas, Inc., Milagro Holdings, LLC and Sequitur Energy Management II, LLC dated October 3, 2012 (incorporated by reference to Exhibit 10.1 to the Quarterly Report on Form 10-Q of Milagro Oil & Gas, Inc. filed on November 13, 2012).                                                                                                                                                                                        |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 10.8              |   | Severance Agreement and Mutual Relapse between Milagro Holdings, LLC and James G. Ivey dated effective December 27, 2012 (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K/A of Milagro Oil & Gas, Inc. filed on January 3, 2013).                                                                                                                                                                                                             |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 21.1              |   | Subsidiaries of Milagro Oil & Gas, Inc. (incorporated by reference to Exhibit 21.1 to the Annual Report on Form 10-K of Milagro Oil & Gas, Inc. filed on March 29, 2013).                                                                                                                                                                                                                                                                                             |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 23.1*             |   | Consent of W.D. Von Gonten &Co.                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 31.1              |   | Certification of Principal Executive Officer. pursuant to Rule 13a-14(a)/Rule 15d-4(a) promulgated under the Securities Exchange Act of 1934, as amended. (incorporated by reference to Exhibit 31.1 to the Annual Report on Form 10-K of Milagro Oil & Gas, Inc. filed on March 29, 2013).                                                                                                                                                                               |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 31.2              |   | Certification of Principal Financial Officer. pursuant to Rule 13a-14(a)/Rule 15d-4(a) promulgated under the Securities Exchange Act of 1934, as amended. (incorporated by reference to Exhibit 31.2 to the Annual Report on Form 10-K of Milagro Oil & Gas, Inc. filed on March 29, 2013).                                                                                                                                                                               |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 32.1              |   | Certification of Principal Executive Officer. pursuant to Rule 13a-14(b)/Rule 15d-4(b) promulgated under the Securities Exchange Act of 1934, as amended, and Section 1350 of Chapter 63 of Title 18 of the United States Code. (incorporated by reference to Exhibit 32.1 to the Annual Report on Form 10-K of Milagro Oil & Gas, Inc. filed on March 29, 2013).                                                                                                         |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 32.2              |   | Certification of Principal Financial Officer. pursuant to Rule 13a-14(b)/Rule 15d-4(b) promulgated under the Securities Exchange Act of 1934, as amended, and Section 1350 of Chapter 63 of Title 18 of the United States Code. (incorporated by reference to Exhibit 32.2 to the Annual Report on Form 10-K of Milagro Oil & Gas, Inc. filed on March 29, 2013).                                                                                                         |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| 99.1*             |   | Reserve report letter as of December 31, 2012, as prepared by W.D. Von Gonten & Co.                                                                                                                                                                                                                                                                                                                                                                                       |
|              |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |

| * | Filed herewith. |
|---|-----------------|

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|                |   | MILAGRO OIL & GAS, INC. |
|---------------------|--------|-----------------------------|
|                |   |                        |
| Date: April 2, 2013 |   | By:                         |   | /s/ Gary J. Mabie |
|                |   |                        |   | Name: Gary J. Mabie |
|                |   |                        |   | Title: President and Chief Operating Officer (Principal executive officer) |

| Signature              |   | Capacity In Which Signed              |   | Date          |
|------------------------|--------|---------------------------------------|--------|---------------|
|                   |   |                                  |
| /s/ Gary J. Mabie      |   | President and Chief Operating Officer |   | April 2, 2013 |
| Gary J. Mabie          |   | (Principal executive officer)         |   |          |
|                   |   |                                  |
| /s/ Robert D. LaRocque |   | Chief Financial Officer and Treasurer |   | April 2, 2013 |
| Robert D. LaRocque     |   | (Principal financial officer)         |   |          |
|                   |   |                                  |
| /s/ Robert D. LaRocque |   | Chief Financial Officer and Treasurer |   | April 2, 2013 |
| Robert D. LaRocque     |   | (Principal accounting officer)        |   |          |
|                   |   |                                  |
| /s/ Jonathan Ginns     |   | Director                              |   | April 2, 2013 |
| Jonathan Ginns         |   |                                  |   |          |
|                   |   |                                  |
| /s/ Mo Bawa            |   | Director                              |   | April 2, 2013 |
| Mo Bawa                |   |                                  |   |          |
|                   |   |                                  |
| /s/ Thomas J. Hauser   |   | Director                              |   | April 2, 2013 |
| Thomas J. Hauser       |   |                                  |   |          |
|                   |   |                                  |
| /s/ Adam Cohn          |   | Director                              |   | April 2, 2013 |
| Adam Cohn              |   |                                  |   |          |