P50 sensory gating deficit has repeatedly been demonstrated in schizophrenia. Studies have produced inconsistent findings with respect to normalization of P50 gating in patients with schizophrenia receiving treatment with different antipsychotics. The current study was designed to determine whether there is a difference in P50 gating in schizophrenia patients treated with first-generation antipsychotics (FGAs) and second-generation antipsychotics (SGAs), including clozapine. P50 evoked potential recordings were obtained from 160 patients with schizophrenia and 77 healthy comparison subjects. Forty-three patients were being treated with clozapine, sixty-eight were taking SGAs (33 risperidone, 21 olanzapine, 11 aripiprazole, and 3 combinations of SGAs) and 49 were being treated with FGAs. Schizophrenia patients exhibited significantly higher P50 ratios than healthy subjects. When patients treated with different antipsychotics were compared, there were no differences in any of the neurophysiological findings. Second-generation antipsychotics were not related to more normal sensory gating in this population of patients with chronic schizophrenia.