Aggressive behavior in schizophrenic patients can often be problematic not only for the patients themselves, but for their families and others. This study examined the effect of electroconvulsive therapy (ECT) in combination with risperidone in an open trial in 10 male schizophrenic patients with significant aggressive behaviors. Patients were given bilateral ECT five times a week in combination with risperidone. The mean total number of times of ECT was 6.6 (range 5–9). The aggressive behavior in five of the six patients, who showed positive symptoms, was rapidly ameliorated within 12 days. The ECT/risperidone regimen also eliminated aggressive behavior in four patients showing no positive symptoms within 10 days. These treatment effects lasted for at least 6 months in 9 (of the 10) patients. The results suggest that ECT, combined with risperidone, produce a rapid and effective elimination of aggressive behaviors in schizophrenic patients. In addition, there was a resolution of aggression in four patients with no positive symptoms. This suggests that aggression in some schizophrenic patients develops as a primary symptom of schizophrenia and is not related to other positive symptoms of the disease or the patient's personality traits.