Eight different electrical dental appliances were tested at different intervals for their ability to interfere with the function of a contemporary cardiac pacemaker. The normal atrial and ventricular pacing was inhibited by an ultrasonic bath cleaner at a distance of less than 15 cm. In contrast, a dental chair, an electrosurgical unit, an ultrasonic tooth scaler, 2 handpieces, and 2 amalgamators failed to produce electromagnetic interference at the minimum distance of 2.5 cm. In conclusion, the results suggest that normal clinical use of dental electrical equipment does not have any significant effect on the cardiac pacemaker tested.