Unidirectional and angle-ply carbon/epoxy laminates were gamma irradiated up to doses of 12 and 20 MGy. Composites with two different, low and high temperature epoxy matrices have been submitted to irradiation and subsequent mechanical testing. The radiation effects were studied by measuring in-plane, interalminar shear and transverse tensile strength, as well as interlaminar strain energy release rate of tested composites. The immersion of composite plate in water at 80 degrees C and mechanical measurements at elevated temperatures emphasized irradiation effects on mechanical properties.