Provided are: a method for producing a polymer composition containing a modified chlorinated polyolefin, which exhibits excellent production stability; and a coating material which contains a polymer composition containing a modified chlorinated polyolefin. According to the present invention, a polymer composition containing a modified chlorinated polyolefin is obtained by copolymerizing polymerizable monomers including (b) a chlorinated polyolefin having an allyloxy group and (c) one or more compounds selected from among (meth)acrylic acid esters, (meth)acrylic acids and styrene in the coexistence of (a) a compound having an allyloxy group and a hydroxyl group.

Provided are: a method for producing a polymer composition containing a modified chlorinated polyolefin, which exhibits excellent production stability; and a coating material which contains a polymer composition containing a modified chlorinated polyolefin. According to the present invention, a polymer composition containing a modified chlorinated polyolefin is obtained by copolymerizing polymerizable monomers including (b) a chlorinated polyolefin having an allyloxy group and (c) one or more compounds selected from among (meth)acrylic acid esters, (meth)acrylic acids and styrene in the coexistence of (a) a compound having an allyloxy group and a hydroxyl group.