Abstract: A thermoplastic multiphase composition is provided which is a melt blend of a functionalized block or graft copolymer and a polyamide. The blend is made from polymers. That is, an elastomeric polymer is blended with a reactive polymer having a functionality which is reactive with the polyamide. This blending occurs under conditions, such as in the presence of free radicals, which lead to the coupling of the elastomeric polymer and the reactive polymer and forms a block or graft copolymer. The graft or block copolymer is then blended with a polyamide. The composition is a multi-phase composition wherein the polyamide is generally a continuous phase, and the block or graft copolymer is present in the form of a particulate dispersed phase. The polyamide compositions have a wide range of improved properties such as good low temperature (e.g., minus 40.degree. C.) impact resistance and good high temperature heat deflection (e.g., 65.degree. C).