In the present study, experimental measurements and numerical solutions on the buckling of single-delaminated glass-fiber composite laminates are carried out on rectangular plates. During the fabrication process, rectangular teflon films of 13 mu m thickness are introduced between plies of different orientation in order to form a macro defect. In addition, the variation in structural configurations, such as ply stacking sequence, width of the delamination, and specimen geometry (width to unsupported length), are considered. In all cases, the delamination is centrally placed through-the-thickness of the laminate. Compression tests are carried out on EP GC 203 glass/epoxy woven composites with built-in single embedded delamination in order to evaluate the critical buckling load. Finite element modeling is used to gain further understanding of the critical buckling load. ANSYS (version 6.1) are used to analyze the critical buckling load of various laminated plates in order to see how changes in the rectangular composite laminated plates would affect the buckling load. A good agreement between finite element predictions and experimental measurements are found for the delamination geometries that were tested.