Novel poly(keto-esters) having carbonyl and oxycarbonyl units randomly combined with linking units derived from olefinic monomers to form an essentially straight-chain polymer backbone are provided. The poly(keto-esters) are produced by converting a portion of the carbonyl functionality of a polyketone to oxycarbonyl groups. The conversion is achieved by reacting the polyketone with an organic peroxyacid in an inert liquid medium at a temperature from -20.degree.C. to 150.degree.C.
