Polyurethane prepolymers containing terminal isocyanate groups in which oleochemical polyols are present as the polyol component. The oleochemical polyols are ring opened products or partial ring-opened products of epoxidized fatty acid triglycerides with alcohols. The use of oleochemical polyols having a residual epoxide number of from 1.0 to 4.0% by weight of epoxide oxygen is preferred. The polyurethane prepolymers are particularly suitable for use in one-component or two-component polyurethane foam formulations.