Sixteen adult males participated in a repeated measures design in which they served as their own control to determine the effects of various amounts of alcohol on: (1) their sexual arousal elicited by erotic motion-pictures, as measured by a penile transducer, (2) the ability to voluntarily inhibit their arousal to those same films in accordance with instructions, and (3) the ability to become voluntarily aroused in the absence of overt stimuli. The ingestion of a low (0.5 or 0.6 ml/kg) or a moderate (1.0 or 1.2 ml/kg) amount of alcohol resulted in a small, but significant, depression of mean sexual arousal, but other measures were not affected. However, the ingestion of a high (1.5 or 1.8 ml/kg) amount of alcohol resulted in every measure of evoked arousal being depressed by a comparatively large degree. The high level of alcohol also affected a very large decrease in sexual arousal when subjects were instructed to become sexually aroused in the absence of overt erotic stimuli. In contrast, none of the three amounts of alcohol caused a significant impairment in the ability of subjects to voluntarily inhibit their sexual arousal, even though most subjects experienced some deterioration in that ability after ingesting a moderate amount of alcohol. The actions of alcohol on sexual responses were not significantly correlated with its effects on a nonsexual matching task, were not related to subjective reports of how alcohol usually affects sexual behavior, and were generally not related to reported drinking history.