**EXHIBIT 31.1**

**CERTIFICATIONS PURSUANT TO**

**SECTION 302 OF**

**THE SARBANES-OXLEY ACT OF 2002**

# **CERTIFICATION**

I,Douglas B. Mackie, Chief Executive Officer, certify that:

1.                                       I have reviewed this quarterly report on Form10-Q of Great Lakes Dredge & Dock Corporation;

2.                                       Based on my knowledge, this quarterly reportdoes not contain any untrue statement of a material fact or omit to state amaterial fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading withrespect to the period covered by this quarterly report;

3.                                       Based on my knowledge, the financialstatements, and other financial information included in this quarterly report,fairly present in all material respects the financial condition, results ofoperations and cash flows of the registrant as of, and for, the periodspresented in this quarterly report;

4.                                       The registrant’s other certifying officer andI are responsible for establishing and maintaining disclosure controls andprocedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e))for the registrant and we 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 thisquarterly report is being prepared;

b)             Evaluated the effectiveness of the registrant’sdisclosure controls and procedures and presented in this quarterly report ourconclusions about the effectiveness of the disclosure controls and procedures,as of the end of the period covered by this quarterly report based on such anevaluation; and

c)              Disclosed in this quarterly report any changein the registrant’s internal control over financial reporting that occurredduring the registrant’s most recent fiscal quarter that has materiallyaffected, or is reasonably likely to materially affect, the registrant’sinternal control over financial reporting.

5.                                       The registrant’s other certifying officer andI have disclosed, based on our most recent evaluation of internal control overfinancial reporting, to the registrant’s auditors and the audit committee ofregistrant’s board of directors (or persons performing the equivalentfunction):

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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)             Anyfraud, whether or not material, that involves management or other employees whohave a significant role in the registrant’s internal control over financialreporting.
| Date:  August 11,  2006 |                    |
|-----------------------------------|-------------------------|
|                              |                    |
|                              | /s/ Douglas B.  Mackie  |
|                              | Douglas B. Mackie       |
|                              | Chief Executive Officer |

 

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