Abstract: Molding compositions which are formed by first pre-reacting a thermoplastic polyester polymer or copolymer with a copolymer of ethylene and a glycidyl acrylate or methacrylate and then subsequently blending with a nucleating agent which is a Group I metal salt of a carboxylic acid to increase the crystallization rate of the polyester. At least one reinforcing component such as glass fibers or reinforcing fillers is preferred. The compositions exhibit a good balance of toughness, rigidity and gasoline resistance and are particularly useful for automotive structural parts such as inner door frames, panels, reinforcements, bumper beams, window surrounds, and other metal replacement applications.