A device for monitoring the air pressure of pneumatic tires of vehicles having a pressure measuring system arranged on the vehicle wheel, the measured values of which are transmitted by means of a transmitter to a receiver, whereby each vehicle wheel is preferably associated with a receiver. The transmitters have a transmitting antenna which is fixed in relation to the wheel and is not integrated into the transmitter. The transmitter is preferably an antenna with several windings which are vulcanized in the side flanks or into the tread of the tire.