The authors recorded event-related potentials (ERPs) in 14 subjects to explore the effects of different hands' responses on ERP components. Subjects used two different fingers of one hand to indicate whether the two sequentially presented visual stimuli were of the same color (match) or not (conflict) in the first half of the test, while they used the other hand in the last half. ERP components of contingent negative variation (CNV), P100, N160, N200, and late positive component (LPC) were recorded in either the match or conflict condition. Component N270 was recorded only in the conflict condition mainly on the centrofrontal area (F3, F4). The mean amplitude of the CNV was significantly higher when subjects used the right hand to respond. The mean amplitudes of N160 in the two conditions and N200 in the conflict condition were significantly higher when the left hand was used to indicate a response. There was no significant difference in the amplitude of N270 between the left-hand and right-hand responses. The N270 is thought to reflect activity in a conflict processing system. The LPC component was not affected by different hands' response-effect.