Abstract: Oxidatively drying aqueous polyurethane dispersions obtainable by reacting drying and/or simidrying oils with low molar mass hydroxy compounds having two or more hydroxyl groups to give compounds containing on average at least one hydroxyl group and at least one radical of a fatty acid having at least one olefinic double bond, then reacting these compounds together with high molar mass polyols, compounds having at least two isocyanate-reactive groups and at least one acid or cation-forming group with polyfunctional isocyanates to give prepolymers having a mass fraction of unreacted isocyanate groups of from 0.1 to 4%, then neutralizing the product and transferring the utilized product to the aqueous phase, a process for preparing them and their use for coating wood.