Abstract: Polyurethanes and polyesters are described which are the reaction products of an aromatic, aliphatic or cycloaliphatic diisocyanate, or of a diacid or diacid derivative respectively, with a diol containing a pendent UV-absorbing moiety, optionally also with one or more other diols or diamines. These UV-absorbing polycondensates can be applied to the surfaces of substrates by exhaustion methods or by spraying and act to protect polymers and dyes from degradation by UV radiation. They are therefore useful, either alone or in combination with other coating materials, for the treatment of wood, paper, textiles, leather or other surfaces which are exposed to degrading radiation.