Investigation of the temporal integration of the acoustic reflex may be complicated by the operating characteristics of the instrumentation used to record the reflex. Several experiments were conducted to determine the operating characteristics of two impedance measuring systems (Madsen, model Z0−70 and Zwislocki Bridge (Grason Stadler, model 3), and to measure selected characteristics of the acoustic reflex, including (1) ’’threshold’’, (2) reflex intensity‐growth functions, and (3) temporal integration functions at ’’threshold’’ for several stimulus frequencies. Results indicate (1) a smaller impedance change may be identified with a Madsen Z0−70 due primarily to the higher S/N (signal‐to‐noise) ratio in that instrument; (2) differences in temporal integration functions obtained between the two instruments were partially accounted for by differences in the operating characteristics of the two measuring systems; (3) the slope of the growth‐intensity function decreases as signal duration decreases; and (4) the slope of the temporal integration function increases as the frequency of the eliciting stimulus increases.