Abstract: Polyamines containing from 0.19 to 20.3 wt % primary amino groups are produced by hydrolyzing in a single stage an isocyanate with an excess of water, a relatively weak basic compound and a water-miscible polar solvent at a temperature from 50.degree. to 165.degree. C. The hydrolysis is conducted in a manner such that the reactants are substantially homogeneous during the reaction. The isocyanate should have an NCO-content of from 0.5 to 40 wt %. The weakly basic compound may be a carbonate or hydrogen carbonate of an alkali metal or an alkali or alkaline earth salt of a monocarboxylic or polycarboxylic acid or mixtures of such materials. The polyamines produced by this process are particularly useful in the production of polyurethanes.