The event-related potentials (ERPs) are voltage changes recorded from the human scalp that is time-locked to a sensory, motor, or cognitive process. Go-NoGo task has been widely used to evaluate response activation and inhibition in normal subjects as well as patients with neuro-psychiatric disorders. NoGo-P3 was thought to be related to response inhibition associated with frontal cortex activity. Accordingly, the NoGo-P3 was found maximal at the fronto-central sites, whereas Go-P3 was found maximal at the centro-parietal sites. The aim of the present study was to investigate habituation of event related potential responses to auditory Go and NoGo stimuli. Thirty-eight healthy male volunteers (ages between 18 and 23 years) participated in the study. ERPs were recorded with 30 electrode sites (international 10/20 system) using an auditory Go-NoGo paradigm. Go tones (1000 Hz) and NoGo tones (2000 Hz) with 50% probabilities were binaurally presented by headphones at 70 dB SPL. The tones were presented in a random series with interstimulus intervals (ISI) of 2 s. The low frequency tones were the target (Go stimuli), and subjects were required to make a button press response to each target with the right index finger. Obtained EEG data from the responses to auditory stimuli in the first and the last half of the task were averaged separately. The amplitudes and latencies of the ERP responses to Go and NoGo stimuli were measured for each task period. The differences between two periods were analyzed by repeated measures analyses of variance (ANOVA). The statistical analyses of the present study show that the NoGo-P3 potential amplitudes were significantly lower in the last half of the task compared to the first half of the task at all leads (p<0.01) while Go-P3 potential amplitudes were not significantly different between the two periods (p>0.05). Also, interaction of the two periods of the task and antero-posterior distribution of the NoGo-P3 potential amplitudes was significant: decrease of the amplitude of NoGo-P3 potential at the fronto-central areas was bigger than the parietal area at the last half of the task compared to the first half of the task (p<0.05). There were no significant differences in latency and amplitude values of N1, P2 and N2 potentials response to auditory Go and NoGo stimuli between the first and the last half of the task (p>0.005). Our results indicate that the NoGo-P3 potential was habituated whereas the Go-P3 potential did not undergo any habitual changes.