A method for controlling the trajectory of a robot, in which, in the cooperative operation of a leading robot having a work tool and a tracking robot gripping a workpiece, the position and the orientation of the work tool may be desirably controlled, even when the interpolative motion is carried out. The robots are cooperatively controlled such that the position and the orientation of a first tool coordinate system set on the work tool attached to the leading robot is moved along a desired trajectory on a second tool coordinate system set on the workpiece gripped by the tracking robot. During a playback operation after a teaching operation, the interpolative position data of the tracking robot is calculated by using the interpolative position data of the leading robot and the relative positions and the relative orientations data of the robots. The invention may be applied to a manual feed. The trajectory may be smoothed by filtering the interpolative position data.