It has been reported that words completed a sentence incongruously produced a significant negative peak at about 400 msec and positive wave component with more prolonged latency following this negative peak. We recorded these potentials that could be important to evaluate semantic adjustment of subjects in depressed patients. Study is performed by using semantically congruous and incongruous sentences in 12 depressed patients and 50 normal controls. In normal group endogen potentials amplitudes were not significantly different between congruous and incongruous sentences and also between normal and depressed patients group. Both normal and depressed groups the latencies of N400 that is elicited by incongruously ended sentences were found shorter than the latencies of N400 of the congruously ended sentences. The finding were compared and discussed under the light of the literature and it is concluded that there weren't cognitive impairment in depression. Finally, in depression it is suggested that reduced amplitudes of positive components that is being with incongruously ended sentences may be due to decreased attention level that is seemed more frequently is this disorder.