This invention relates to radiopaque polyurethane compositions which are reaction products of(a) cycloaliphatic diisocyanates;(b) at least one polyether diol having a molecular weight of from about 500 to about 6000; and(c) an isocyanate-reactive bromine-containing compound selected from the group consisting of(i) tetrabromodipentaerythritol and(ii) a mixture of tetrabromodipentaerythritol and dibromoneopentyl glycol; and(d) optionally, a catalyst;wherein the amount of component (c) is such that bromine constitutes at least 15% by weight of the polyurethane composition, wherein the weight ratio of component (b) to component (c) is from about 2:98 to about 55:45, and wherein the components are reacted at an isocyanate index of from about 95 to about 120.