The aim of the present study was to investigate the effect of second-generation antipsychotics (clozapine or another second-generation antipsychotic) on perceptual abnormalities related to sensory gating deficit. Although clozapine is known to improve sensory gating assessed neuro- physiologically, we hypothesized that patients with schizophrenia treated with clozapine would report less perceptual abnormalities related to sen- sory gating deficit than patients treated with other second-generation anti- psychotics do. Forty patients with a diagnosis of schizophrenia were investigated (10 patients treated with clozapine and 30 patients treated with another second-generation antipsychotic drug). Perceptual abnor- malities were assessed with the Sensory Gating Inventory. Sensory gating was assessed through electroencephalogram with the auditory event- related potential method by measuring P50 amplitude changes in a dual click conditioning-testing procedure. Patients treated with clozapine pres- ent normal sensory gating and report less perceptual abnormalities related to sensory gating than patients treated with other second-generation anti- psychotics do. Although the cross-sectional design of this study is limited because causal inferences cannot be clearly concluded, the present study suggests clinical and neurophysiological advantages of clozapine com- pared with other second-generation antipsychotics and provides a basis for future investigations on the effect of this treatment on perceptual abnor- malities related to sensory gating deficit in patients with schizophrenia.