Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We hereby consent to the incorporation by reference in the Registration Statements (Form S-8 No. 333-70259 and No. 333-38090) pertaining to the LMI Aerospace, Inc. Profit Sharing and Savings Plan and Trust, the Amended and Restated LMI Aerospace, Inc. 1998 Stock Option Plan, and the 1989 Employee Incentive Stock Option Plan of our report dated March 25, 2005 relating to the consolidated financial statements and financial statement schedule of LMI Aerospace, Inc., which appears in this Form 10-K for the year ended December 31, 2004.

/s/ BDO Seidman, LLP

Chicago, Illinois

March 31, 2005