A process for producing polyurethane foam articles is described, in which the article is produced in the conventional manner by foaming in a mould and a release agent is applied to the mould surface prior to filling with the foam-producing components. According to the invention, a solvent-free, aqueous release agent is used in combination with one or more alkali metal and/or ammonium salts of higher fatty acids and one or more higher alcohols and the combination is applied in the hot state, preferably at a temperature of at least 75.degree. C. to the mould surface. In addition, an additive is described, which is suitable for performing the process according to the invention and contains one or more alkali metal and/or ammonium salts of higher fatty acids, one or more higher alcohols and otherwise water. The process according to the invention has the advantage that it not only avoids the use of environmentally prejudicial organic solvents, but also leads to excellent release agent films, from which the water is very largely evaporated within a very short time and namely within the very short cycle times of modern foam plants.