In this paper, the effects of the delaminations size on the critical buckling load and compressive failure load of E-glass/epoxy composite laminates with multiple large delaminations are studied. A numerical and experimental study is carried out to determine the buckling load of rectangular composite plates. For the experiments (0 degrees/90 degrees/0 degrees/90 degrees)s oriented cross-ply laminated plates with multiple large delaminations and without delamination are produced by using hand lay-up technique. The experimental buckling loads of plates are found by clamping from the two edges and then these results are compared with the results obtained by ANSYS11.0 package. In addition, the compressive failure loads of composite laminates containing multiple large delaminations are found by compression test fixture. It is found that the longest and near-surface delamination size influences the buckling load and compressive failure load of composite laminates. However, the size of beneath delaminations has no significant effect on the buckling load and compressive failure load of composite laminates. (C) 2008 Elsevier Ltd. All rights reserved.