Abstract: A biomedical centrifuge having a rotor in the form of a body having rotational symmetry wherein, from a surface area thereof, cavities are provided which accommodate substantially cylindrical vessels. The cavities--as viewed in a plane normal to the axis of rotation of the rotor--are located at the angular points of a regular polygon. There is also provided a motor for rotating the rotor at a speed of many tens of thousands r.p.m. The rotor body is made of a cap-shaped frame of synthetic plastics material and the cavities are provided in the plastics material. The remainder of the frame is substantially hollow. On its radially outer the periphery, the frame is surrounded by reinforcing rings or a reinforcing envelope made of substantially tangentially oriented long fibres of suitable material.