Abstract: In a method of measuring rheological properties of a sample, an oscillation system containing the sample is caused to perform free oscillations, and the damping caused by the sample is determined, the rheological properties of the sample being possible to determine by means of the damping. By this method, rheological properties can be determined for samples of a small volume and/or low viscosity. The method is especially adapted to measure body fluids. A rheometer for carrying out the method is also disclosed.