Abstract: Method for the continuous control of the delivery rate of reciprocating compressors by occasional holding-open of the suction valves by a lifting device (8), which is actuated by a lifting force supplied by a pressure medium. In order to take into consideration the properties of the gas delivered and to adapt the control method in a corresponding manner, the magnitude of the lifting force is chosen depending on the drive power respectively received by the drive motor (11) of the compressor (3). The lifting force may be limited depending on the drive power. An apparatus for carrying out the method includes a compressor system (3), which includes at least one cylinder (4-7) with a lifting device (8) for the suction valve, which is actuated by a lifting force applied by a pressure medium, the magnitude of which can be determined by a controller (10). The drive power received by the drive motor (11) of the compressor (3) is supplied to the controller (10) as a signal.