A wireless dental apex locator (10) for use in determining the location of the apex of a patient's root, includes an electronic module (13) having a battery power source (13a), an impedance analyzer circuit (13b) and a radio frequency transmitter (13c); a grounding module (12) having a clip (15) for grounding the patient; a probe module (14) having an endodontic probe (21); and an associated but not physically connected display unit (11) having a receiver (31) for receiving radio frequency signals from the transmitter (13c). The display unit (11) has an electronic circuit that conditions the signals and interprets the signal for display on a graphic display (31).