The impact energy absorption characteristics of glass epoxy composites and glass polyester composites with respect to fiber volume fraction were investigated by the instrumented Charpy impact test method. Also, the interlaminar shear properties were measured by the short beam shear test to investigate the correlation between the interlaminar shear properties and the impact energy absorption characteristics. Appropriate curing cycle was suggested for polyester resin by measuring the dissipation factor. Using the experimental results, the impact absorption characteristics of glass fiber composites such as fiber breakage and fiber pull-out and delamination were discussed.