Event-related potentials (ERPs) were elicited with an auditory discrimination paradigm in 20 adult female subjects on the first day of their menstrual cycles and approximately 14 days later. The amplitude and latency of the N1, P2, N2 and P3 (P300) components were measured for the two assessment times. No differences in either amplitude or latency for any of the components were observed as a function of menstrual cycle. Half the subjects who took oral contraceptives were compared to the other half who did not. No differences or interactions between these subgroups were obtained for any component amplitude or latency. It was concluded that menstrual cycle and use of oral contraceptives do not affect the P3 or other ERP components.