PURPOSE: To obtain a coating composition which is very practicable and is further in compatibility of a chlorinated polyolefin with an acryl or vinyl copolymer, adhesion to a polyolefin substrate, intercoat adhesion and solvent resistance in use as a primer and weather resistance and chemical resistance in use as a topcoating material.

CONSTITUTION: A coating composition comprising as an essential film-forming component, a graft copolymer obtained by copolymerizing a specified chlorinated polyolefin with a hydroxylated vinyl monomer, an unsaturated carboxylic acid, and another vinyl monomer copolymerizable therewith and optionaly a polyester resin containing a copolymerizable, ethylenically unsaturated bonds in the presence of an organic solvent.