A patient rotation system for rotating the body of a patient comprises an air inflatable cushion having two elastic exterior surfaces, e.g. of stretch material, wherein one of said two elastic surfaces of said cushion forms the top surface, and the other one forms the bottom surface. In deflated state the cushion has a flat shape and in inflated state the two elastic surfaces bulge away from each other, such that inflation of the cushion causes the cushion to assume a wedge shape thereby rotating the body around said rotation axis. The cushion is embodied as a unitary, semi-rigid, portable board when in its deflated state, which enables the sliding of the deflated cushion in between the body of the patient and a horizontal surface, on which the body is lying in supine position, until its posterior support points are being supported by the cushion at its top elastic surface.