**Exhibit 31.1**

 

Certification of PrincipalExecutive Officer

Pursuant toRule 13a-14(a) under theSecurities Exchange Act of 1934

 
| I, Michael J. Mauceli, certify that: |
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| 1.                                   |   | I  have reviewed this Annual Report on Form 10-K of Reef Global Energy IX,  L.P. for the fiscal year ended December 31, 2007; |
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| 2.                                   |   | Based  on my knowledge, this annual report does not contain any untrue statement of  a material fact or omit to state a material fact necessary to make the  statements made, in light of the circumstances under which such statements  were made, not misleading with respect to the period covered by this report; |
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| 3.                                   |   | Based  on my knowledge, the financial statements, and other financial information  included in this report, fairly present in all material respects the  financial condition, results of operations and cash flows of the registrant  as of, and for, the periods presented in this report; |
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| 4.                                   |   | The  registrant’s other certifying officer(s) and I are responsible for  establishing and maintaining disclosure controls and procedures (as defined  in Exchange Act Rules 13a-15(e) and 15d-15(e)), and internal  control over financial reporting (as defined in Exchange Act  Rules 13a-15(f) and 15d-15(f)) for the registrant and have: |
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|                                 | a) | Designed such  disclosure controls and procedures, or caused such disclosure controls and  procedures to be designed under our supervision, to ensure that material  information relating to the registrant, including its consolidated  subsidiaries, is made known to us by others within those entities,  particularly during the period in which this report is being prepared; |
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|                                 | b) | Designed such internal  control over financial reporting, or caused such internal control over  financial reporting to be designed under our supervision, to provide reasonable  assurance regarding the reliability of financial reporting and the  preparation of financial statements for external purposes in accordance with  generally accepted accounting principles; |
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|                                 | c) | Evaluated the  effectiveness of the registrant’s disclosure controls and procedures and  presented in this report our conclusions about the effectiveness of the  disclosure controls and procedures, as of the end of the period covered by  this report based on such evaluation; and |
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|                                 | d) | Disclosed in this  report any change in the registrant’s internal control over financial  reporting that occurred during the registrant’s fourth fiscal quarter that  has materially affected, or is reasonably likely to materially affect, the  registrant’s internal control over financial reporting. |
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| 5.                                   |   | The  registrant’s other certifying officer and I have disclosed, based on our most  recent evaluation of internal control over financial reporting, to the  registrant’s auditors and the audit committee of registrant’s board of  directors (or persons performing the equivalent functions): |
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|                                 | a) | All significant  deficiencies and material weaknesses in the design or operation of internal  control over financial reporting which are reasonably likely to adversely  affect the registrant’s ability to record, process, summarize and report  financial information; and |
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|                                 | b) | Any fraud, whether or  not material, that involves management or other employees who have a  significant role in the registrant’s internal control over financial  reporting. |
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| Date:  April 15, 2008 | By:  Reef Oil & Gas Partners, L.P. |
|----------------------------|---------------------------------------------|
|                       | Managing  General Partner                   |

 
|   | By:  Reef Oil & Gas Partners, GP, LLC |
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|   | By:                                            | /s/  Michael J. Mauceli |
|   | Michael  J. Mauceli                            |
|   | Manager  and Member                            |
|   | (Principal  Executive Officer)                 |

 

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