The invention relates to a method for monitoring the functionality of an actuator (1) having a pneumatic drive (2), in particular for monitoring an actuator (1) for a safety valve, including a magnetic valve (4) for controlling the pneumatic drive (2), wherein the magnetic valve (4) is monitored by means of a pressure measurement and is, for this purpose, connected to a first pneumatic conduit (16) to a position controller (3) of the actuator (1) as well as to the pneumatic drive (2) to a second pneumatic conduit (17). The magnetic valve (4) is switched off and on again with a switching time (t2−t1). The switching time (t2−t1) of the magnetic valve (4) is detected at which, at the one hand, the switching time (t2−t1) is so short that the position of the actuator (1) remains essentially constant or unchanged and, on the other hand, it is, however, so long that a pressure drop (dp=P1−P2) in the first pneumatic conduit (16) in front of the magnetic valve (4) is present after switching the magnetic valve (4) on again.