The present invention provides a resin composition excellent in solvent resistance, mechanical properties, heat resistance, and processability which comprises:100 parts by weight of a composition comprising (A) 5-94 wt % of a modified polyphenylene ether resin and (B) 95-5 wt % of a thermoplastic polyester,(C) 0-100 parts by weight of a rubber-like polymer, and(D) 0.01-10 parts by weight of an amino resin obtained by modifying with an alcohol an addition reaction product of formaldehyde and at least one compound selected from the group consisting of melamine, guanamine and urea.