A numerical/experimental method for identification of material parameters of composite materials is proposed in this paper. This method combines experimental techniques for the determination of vibration eigenfrequencies of plates made of composite materials along with a finite element numerical method for the determination of the corresponding numerical eigenfrequencies. The identification process makes use of optimization techniques, through the minimization of an error measurement that estimates the deviation between numerical and experimental eigenvalues, for a given set of material parameters. The accuracy of the proposed technique is discussed through test cases.