Abstract: An electronic test instrument for rapid comprehensive verification of correct operation of medical pacers. This portable microprocessor-based test instrument includes a device for measuring and displaying pacer characteristics including pacing rate, pulse duration, pulse amplitude, sensitivity, sensed refractory interval, stimulus refractory interval, atrio-ventricular delay, D.C. leakage, susceptibility to A.C. interference, frequency response and battery drain. The test instrument includes a device for selecting each test and entering associated parameters, a device to convert the analog pacer pulses to digital values for detection and measurement, a device to generate variable amplitude test waveforms and apply them to a medical pacer at a specified rate or at a specified delay from a previous pacer pulse or with a specified delay between two test waveforms and a device for displaying test results.