Event-related potentials (ERPs) have been used to investigate cognitive dysfunction in alcoholics. Previous findings are not concordant. Thirty alcoholics, and sex and age matched healthy controls (N = 30) were tested. The average age of alcoholics and the controls were 43.8 +/- 10.3 years and 44.7 +/- 11.5 years, respectively. All subjects were right handed and free from medication. Alcoholics met the criteria of DSM-III-R for alcohol dependence. ERPs were recorded during presentation of auditory stimuli. The stimuli consisted of 1kHz tone bursts referred to as 'frequent (non-target) stimuli' and 2kHz tone-bursts referred to as 'rare (target) stimuli'. The probability of frequent stimuli and rare stimuli were 0.8 and 0.2, respectively. The amplitudes of N100 and P300 were smaller in alcoholics than the controls. However, the latencies of these components were not different between the groups. The amplitudes and latencies of both N200 and P200 were not different between two subject groups. Although in the controls the maxima of P300 were seen only at parietal region, in alcoholics P300 maxima were seen at parietal region (16 out of 30, 53.3%), at frontal region (11 out of 30, 36.7%) and at occipital region (3 out of 30, 10.0%). Correlations between the distributions of P300 maxima and brain CT findings were examined in alcoholics. While CT abnormalities were been in 2 out of 19 (10.5%) subjects having P300 maxima at pareital region, in subjects having P300 maxima at frontal region the abnormalities were seen in 10 out of 11 subjects (90.9%). Correlations between values of CT measurements and the amplitudes (Pz) of P300 were examined.(ABSTRACT TRUNCATED AT 250 WORDS)