**Exhibit 31.1**

Certification ofPrincipal Executive Officer

Pursuant to Rule13a-14(a) of theSecurities Exchange Act of 1934

I, Michael J.Mauceli, certify that:

1.               I have reviewedthis quarterly report on Form 10-Q for the fiscal quarter ended June 30, 2007of Reef Global Energy IX, L.P.;

2.               Based on myknowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report;

3.               Based on myknowledge, the financial statements, and other financial information includedin this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, andfor, the periods presented in this report;

4.               The registrant’sother certifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e)and 15d-15(e)) for the registrant and have:

a)              Designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our supervision, to ensure that material information relating to theregistrant, including its consolidated subsidiaries, is made known to us byothers within those entities, particularly during the period in which thisreport is being prepared;

b)             Evaluated the effectiveness of theregistrant’s disclosure controls and procedures and presented in this reportour conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and

c)              Disclosed in this report any change inthe registrant’s internal control over financial reporting that occurred duringthe registrant’s most recent fiscal quarter (the registrant’s fourth fiscalquarter in the case of an annual report) that has materially affected, or isreasonably likely to materially affect, the registrant’s internal control overfinancial reporting; and

5.               The registrant’sother certifying officer and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to the registrant’sauditors and the audit committee of registrant’s board of directors (or personsperforming the equivalent functions):

a)              All significant deficiencies and materialweaknesses in the design or operation of internal control over financialreporting which are reasonably likely to adversely affect the registrant’sability to record, process, summarize and report financial information; and

b)             Any fraud, whether or not material, thatinvolves management or other employees who have a significant role in theregistrant’s internal control over financial reporting.
| Date: August 20, 2007 | By:                            | Reef Oil & Gas Partners, L.P.     |
|-----------------------|--------------------------------|---------------------------------------|
|                  | Managing General  Partner      |
|                  |                           |                                  |
|                  | By:                            | Reef Oil &  Gas Partners, GP, LLC |
|                  |                           |                                  |
|                  | By:                            | /s/ Michael J. Mauceli                |   |
|                  | Michael J.  Mauceli            |
|                  | Manager and  Member            |
|                  | (principal  executive officer) |

 

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