A motor-adjustable head rest for operating tables comprises a head plate (12) which is arranged at one end of a curved support shaft (24) which, in a plane which is perpendicular with respect to the axis of curvature, is guided in an adjustable manner on a support between three rollers (26, 28, 30) which are spaced from one another in the direction of adjustment, which support can be connected to the operating table. The tracks (32, 34, 36) for the rollers (26, 28, 30) which are formed on the support shaft (24) are shaped such that their instantaneous curvature centers in each position of the support shaft (24) coincide with the instantaneous center of rotation of the head movement during the lifting and the lowering of the patient's head (14) resting on the head plate (12).