An examination was made of the influence of the concentration of the compatibiliser-a graft copolymer of polystyrene with maleic anhydride-on the compatibility of a polyamide-polystyrene blend in a wide range of ratios. The influence of the length and frequency of distribution of the graft chains of the graft copolymer on the compatibility and deformation and strength properties of the polyamide-polystyrene blend was established.