Widely divergent amounts of perstimulatory adaptation have been reported previously, possibly due to differences in technique of measurement. One method often used determines perstimulatory adaptation from a series of simultaneous binaural loudness balances between a continuous stimulus in the adapting ear and a stimulus intermittently presented to the test ear. The present study attempts to evaluate the effect of the characteristics of intermittency of the test stimulus upon the measured adaptation in the adapting ear. With a 4000‐cps adapting tone presented at 75‐db sensation level, 16 combinations of on‐ and off‐duration of the test tone were investigated using 11 listeners. For all experimental conditions the adapting curves showed the same general shape, with a rapid initial decline, followed by a more gradual decline reaching asymptote after 5 to 6 min. As the on‐time of the test stimulus increased, less adaptation was seen, except for off‐times of 30 sec or greater where on‐time no longer influenced adaptation. This is interpreted as indicating that greater amounts of adaptation took place in the test ear as on‐time was lengthened; but for the stimuli used, 30 sec was sufficient for recovery to occur. In general, however, variation in on‐time produced greater changes in measured adaptation than did similar changes in off‐time of the test stimulus.