Eleven resins and composites (glass-fiber reinforced resins) were selected for high temperature testing. Comparative data are presented on the room-temperature properties, the tensile strength at elevated temperatures and the stress-relaxation behavior of the eleven materials, which include polyimide, ETFE, FEP, polyphenylene sulfide, polyethersulfone, nylon 6/6, polyester, polysulfone, polyarylsulfone, poly-p-oxybenzoate and polyamide-imide.