A process for the preparation of an aliphatic, cyclo-aliphatic, and/or aliphatic-cycloaliphatic di- and/or polyurethane comprising the steps ofA. reacting a primary aliphatic, cycloaliphatic, and/or aliphatic-cycloaliphatic di- and/or polyamine with a carbamate in the presence of alcohol at temperatures of 160.degree. C. to 300.degree. C., andB. separating the ammonia and other by-products from the aliphatic, cycloaliphatic, and/or aliphatic-cycloaliphatic di- and/or polyurethane.One or more catalysts may be added to the reactants to increase the reaction rate. The aliphatic, cycloaliphatic, and/or aliphatic-cycloaliphatic di- and/or polyurethanes produced are valuable end and intermediate products. They can be transferred into the corresponding isocyanates which can then be used for the preparation of polyurethanes.