The utilization of leaky plate waves in a scanning arrangement has exhibited improved reliability and increased sensitivity to important defects in unidirectional material [1,2,3].The application of frequency modulation to the usual tone burst signal used to generate plate waves has also been shown to enhance defect discrimination [2,3].In the current work, leaky plate wave techniques have been applied to the inspection of biaxially laminated graphite-epoxy composites.Test samples having 8, 16, and 24 plies, respectively, are studied.Test specimens contain several types of defects — simulated delaminations, porosity, and ply cuts.In addition, a series of impact-damaged samples are examined to study the method’s sensitivity to this type of delamination.All simulated defects were detected, and comparisons with conventional normal-incidence C-scan measurements have shown that the plate wave technique is more sensitive to both porosity and ply cuts, consistent with our observations on uniaxial composites [3]. Novel gating methods have been applied to the plate wave spectra to improve defect detection in biaxial composites.