The present invention relates to a polyamide resin composition comprising a polyamide resin (A) and a modified polyester elastomer (b) prepared by the reaction of a polyester elastomer with a monomer selected from among unsaturated carboxylic acids and derivatives thereof, which have excellent characteristics in elasticity, chemical, oil, impact resistance and moldability. The resin compositons can be widely used for automobile parts and various kinds of machine parts etc.