Coating compositions comprise a copolymer of ethylenically unsaturated monomers adapted to be cross-linked on heating, said copolymer being blended with 5 to 30% by weight of the monomers of compatible resin which is a rubbery copolymer, a nylon, or a copolymer of styrene a substituted styrene, a mono-olefin, an alkyl acrylate or an alkyl methacrylate; a cross-linking agent for said copolymer when the copolymer does not contain mutually reactive sites; and a cross-linking catalyst. Specified monomers are styrene, alkylated styrenes, acrylic and methacrylic esters, vinyl chloride, acrylonitrile, b -hydroxyethyl methacrylate, a ,b -unsaturated acids and amides thereof, vinyl pyridines, dimethylaminoethyl methacrylate. Specified compatible resins are copolymers of butadienes with styrene, methyl methacrylate or acrylonitrile, polyamides and polyesteramides, copolymers of styrene with acrylic and methacrylic esters, and copolymers of ethylene and propylene with basic monomers. Specified cross-linking agents are aminoplasts, e.g. condensates of formaldehyde with urea, melamine or benzoquanamine, and polyepoxides, e.g. vinyl cyclohexene dioxide and condensates of epichlorhydrin with diphenylol propane or glycerol. Examples describe the copolymerization of (1) vinyl toluene, ethyl acrylate and acrylic acid and (3) ethyl acrylate and acrylamide in xylene and butanol in the presence of benzoyl and t.-butyl hydroperoxide, and (I) ethyl acrylate and dimethylaminoethyl methacrylate in toluene in the presence of azodiisobutyronitrile; and coating compositions pigmented with titanium dioxide and comprising (1 and 2) vinyltoluene/ethyl acrylate/acrylic acid copolymer, ethyl acrylate/dimethylaminoethyl methacrylate copolymer, a condensate of epichlorhydrin and diphenylol propane and dimethyl (coconut oil residue) amine; (3) vinyl toluene/ethyl acrylate/acrylic acid copolymer, ethyl acrylate/acrylamide copolymer, condensates of epichlorhydrin with diphenylol propane or glycerol and dimethyl (coconut oil residue) amine; (4) vinyl toluene/ethyl acrylate/acrylic acid copolymer, butyl acrylate/acrylamide copolymer, a condensate of epichlorhydrin and diphenylol propane and dimethyl (coconut oil residue) amine; (5) vinyl toluene/ethyl acrylate/acrylic acid copolymer, and a copolymer of acrylamide with ethyl acrylate or methyl methacrylate, a copolymer of butadiene, methyl methacrylate and dimethylaminoethyl methacrylate or a copolymer of styrene and 2-vinyl pyridine, and polyepoxides; (6) vinyl toluene/ethyl acrylate/acrylic acid/glycidyl methacrylate copolymer and ethyl acrylate/acrylamide copolymer; (7) styrene/ethyl acrylate/acrylamide copolymer, ethyl acrylate/acrylic acid copolymer, butylated urea/formaldehyde resin or hexamethyl ether of hexamethylol melamine and p-toluene sulphonic acid; and (8) p-toluene sulphonic acid and an ethyl acrylate/acrylamide copolymer with a methyl methacrylate/acrylic acid copolymer or a methyl methactylate/ethyl acrylate/acrylic acid copolymer with a methylated methylol melamine; an ethyl acrylate/acrylic acid copolymer with a styrene/ethyl acrylate/acrylamide/N-methylol acrylamide copolymer and a condensate of epichlorhydrin and diphenylol propane; and an ethyl acrylate/acrylamide copolymer with a vinyl toluene/ethyl acrylate/acrylic acid/hydroxybutyl acrylate copolymer and a methylated methylol melamine or butylated urea/formaldehyde resin. Specifications 681,031, 731,046, 777,769, 842,641, 877,236 and 880,356 are referred to.ALSO:Substrates, e.g. metals, are coated e.g. by spraying a solution in an organic solvent, with compositions comprising a copolymer of ethylenically unsaturated monomers adapted to be crosslinked on heating, said copolymer being blended with 5-30% by weight of the monomers of compatible resin which is a rubbery copolymer, a nylon, or a copolymer of styrene, a substituted styrene, a monoolefin, an alkyl acrylate or an alkyl methacrylate; a crosslinking agent for said copolymer when the copolymer does not contain mutually reactive sites; and a crosslinking catalyst; and the coatings cured by heating. Specified monomers include styrene, alkylated styrenes, acrylic and methacrylic ester, vinyl chloride, acrylonitrile, a ,b -unsaturated acids and amides thereof, b -hydroxyethyl and dimethylaminoethyl methacrylates and vinyl pyridines. Specified compatible resins include copolymers of butadiene with styrene, methyl methacrylate or acrylonitrile, polyamides and polyesteramides, copolymers of styrene with acrylic and methacrylic esters, and copolymers of ethylene and propylene with basic monomers. Specified crosslinking agents are aminoplasts and polyepoxides. Examples describe the coating of phosphated steel panels with coating compositions pigmented with titanium dioxide and comprising (1 and 2) vinyl toluene/ethyl acrylate/acrylic acid copolymer, ethyl acrylate/dimethyl/aminoethyl methacrylate copolymer, epichlorhydrin/diphenylol propane condensate and dimethyl (coconut oil residue) amine; (3) vinyl toluene/ethyl acrylate/acrylic acid copolymer, ethyl acrylate/acrylamide copolymer, condensates of epichlorhydrin with diphenylol propane or glycerol and dimethyl (coconut oil residue) amine; (4) vinyl toluene/ethyl acrylate/acrylic acid copolymer, butyl acrylate/acrylamide copolymer, epichlorhydrin/diphenylol propane condensate and dimethyl (coconut oil residue) amine; (5) vinyl toluene/ethyl acrylate/acrylic acid copolymer and a copolymer of acrylamide with ethyl acrylate or methyl methacrylate, a butadiene/methyl methacrylate/dimethylaminoethyl methacrylate copolymer an a styrene/2-vinyl pyridine copolymer, and polyepoxides; (6) vinyl toluene/ethyl acrylate/acrylic acid/glycidyl methacrylate copolymer and ethyl acrylate/acrylamide copolymer; (7) styrene/ethyl acrylate/acrylamide copolymer, ethyl acrylate/acrylic acid copolymer, butylated urea/formaldehyde resin or hexamethyl ether of hexamethylol melamine and p-toluene sulphonic acid; and (8) p-toluene sulphonic acid and an ethyl acrylate/acrylamide copolymer with a methyl methacrylate/acrylic acid copolymer or a methyl methacrylate/ethyl acrylate/acrylic acid copolymer with a methylated methylol melamine; an ethyl acrylate/acrylic acid copolymer with a styrene/ethyl acrylate/acrylamide/N-methylol acrylamide copolymer and an epichlorhydrin/diphenylol propane condensate; and an ethyl acrylate/acrylamide copolymer with a vinyl toluene/ethyl acrylate/acrylic acid/hydroxybutyl acrylate copolymer and a methylated methylol melamine or butylated urea/formaldehyde resin; the coatings being cured by baking. Specifications 681,031, 731,946, 777,769, 842,641, 877,236 and 880,356 are referred to.