Rotary vane vacuum pumps are devices widely used in various types of industries. A three-phase electric motor, which is a usual drive source in this group of devices, propels rotor, which is eccentric placed in the cylinder. The combination of this arrangement, between cylinder and rotor, with centrifugal force, forces the vanes to move out and into its slots milled in the rotor. As a result, the increase and decrease of the inter-vane volume occur, causing the air to be sucked into the pump. Due to improper exploitation, there is a possibility of a mechanical damage to the vane, and in some cases the vane can fall out of its groove, what leads to catastrophic failure. The article presents a new method for diagnostics of vanes, based on the observation and analysis of a pressure signal, generated by a rotary vane vacuum pump.