Process for the production of leather, wherein pelts, pickled pelts or semifinished products are treated with at least one copolymer (A) which is obtainable by copolymerization of the following comonomers: (a) at least one ethylenically unsaturated C.sub.3-C.sub.10-carboxylic acid or at least one ethylenically unsaturated C.sub.4-C.sub.10-dicarboxylic acid or its anhydride, (b) at least one (meth)acrylate of an .alpha.-branched C.sub.3-C.sub.10-alkanol, (c) at least one (meth)acrylate of a primary C.sub.4-C.sub.20-alkanol.