Abstract: A cardio-pulmonary resuscitation (CPR) aid is disclosed. It is in the form of a wrist watch (10) having a set of auxiliary push buttons (13, 14 and 15). When a push button (13, 14 or 15) is pressed, audible signals are emitted from a beeper (16) at a rate dependent on which of the push buttons (13, 14 or 15) is pressed for use in timing external heart massage. The appropriate one of a set of push button lights (23, 24 or 25) associated with respective ones of the push buttons (13, 14 or 15) flashes in synchronism with the audible signals for timing CPR in noisy areas. The watch also records the elapsed time since the initiation of the CPR signals and the number of timing signals produced.