The Izod impact strength and tensile properties of blends Nylon 6 and maleated ethylene-propylene rubber (EPR-g-MA) reinforced with glass fiber as a function of glass fiber and EPR-g-MA content were examined. Materials containing 0-20 wt% glass fiber and 0-20 wt% EPR-gMA were formulated. The modulus and yield strength of the unreinforced materials decreased as EPR-g-MA content increased. This effect can be completely counteracted by the addition of more than 10 wt% glass fiber, regardless of rubber content, with blends containing 20 wt% glass fiber showing substantially higher modulus than that of Nylon 6. Izod impact strength of super-tough blends was reduced by similar to 50% with the addition of small amounts of glass fiber; however, these glass fiber reinforced, rubber-toughened blends still retain a high impact strength. (C) 2000 Elsevier Science Ltd. All rights reserved.