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EXHIBIT 31.1 CERTIFICATION
PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 I, John E. Jackson, certify that: 1. I have reviewed this Annual Report on Form 10-K of Hanover Compressor Company; 2. Based on my knowledge, this 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; 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; 4. The registrants other certifying officers 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-15f
and 15d-15(f)) for the registrant and we have:  (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;(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;(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(d)
    Disclosed in this report any change in the registrants internal control over financial
reporting that occurred during the registrants most recent fiscal quarter (the registrants
fourth fiscal quarter in the case of an annual report) that has materially affected, or is
reasonably likely to materially affect, the registrants internal control over financial
reporting; and 5. The registrants other certifying officers 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 the registrants board of directors (or persons performing the equivalent functions):  (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(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. Date: March 14, 2005 By:
    
    /s/ JOHN E. JACKSONName:
    
    John E. JacksonTitle:
    
    Chief Executive Officer and President
(Principal Executive Officer)