Electrical signals attributed to lightning events on Venus have been observed by instruments abroad Veneras 11 and 12 [Ksanfomaliti, 1980> and aboard the Pioneer Venus Orbiter [Taylor et al., 1979>. This paper reports the results of a search for optical pulses from the dark side of Venus made with the star sensor aboard the oneer Venus Orbiter. A comparison of both the frequency and amplitude distributions of received pulses with those of control experiments in which the star sensor observed deep space showed no statistically significant differences. Based on observations made during orbits 300 through 345, an upper limit of 30 flashes/km2/yr has been derived for the average lightning frequency on the dark side of Venus. This value assumes that the amplitude distribution of lightning and the attenuation of the optical pulse by clouds on Venus are not substantially different from the occurring on Earth.