High-molecular weight polycarbonate elastomers are produced by reacting polymer segments having an average molecular weight (Mn) of more than 600 and carboxyl groups with diphenols and phosgene according to the two-phase boundary polycondensation process at a pH value between about 9 and about 14 and a temperature between about 0.degree. C. and 80.degree. C. and, thereafter, either heat-treating the resulting reaction products at temperatures between about 40.degree. C. and about 100.degree. C. or gelling the resulting reaction products in solution in organic solvents.