Method for engaging and disengaging a hydraulic motor which is adjustable in its displacement from and to a hydrostatic drive train of a hydromechanical transmission with a closed hydraulic fluid circuit. Two adjustable hydraulic motors and a hydraulic pump are arranged in parallel in the hydrostatic drive train and connected to a mechanical drive on the output side. At least one of the two hydraulic motors is connected to the mechanical drive via an assigned clutch. As appropriate to the driving situation, during operation of the other hydraulic motor and the hydraulic pump at least one of the hydraulic motors is engaged via the assigned clutch with the hydromechanical transmission from which the hydraulic motor was previously disengaged, likewise as appropriate to the driving situation. Before closing the clutch, the hydraulic motor to be engaged is accelerated load-free by deflecting its adjustment device in such a way that the rotational speed of an assigned clutch input shaft of the clutch is at least equal to the rotational speed of the clutch output shaft of the clutch which is connected to the mechanical gear. When the clutch is closed, both hydraulic motors act on a common output shaft of the mechanical gear.