The cause of restless legs syndrome (RLS) has not yet been ascertained, but one of the most promising theories involves dopaminergic deficiency. In accordance with this theory, we assumed that the prevalence of RLS would be higher among schizophrenics treated with antipsychotics than in the normal population. The purpose of this study was to establish the prevalence, characteristics, and clinical correlates of RLS in schizophrenic patients undergoing treatment with antipsychotics. A total of 182 hospitalized schizophrenic patients and 108 age- and sex-matched normal controls were enrolled. The presence of RLS and its severity were assessed using the International Restless Legs Syndrome Study Group (IRLSSG) diagnostic criteria and the IRLSSG rating scale, respectively. The Athens Insomnia Scale (AIS), Brief Psychiatric Rating Scale (BPRS), and Barnes Akathisia Rating Scale (BARS) were used to evaluate insomnia, global psychiatric symptoms, and akathisia, respectively, in schizophrenic patients. Of the 182 schizophrenic patients, 39 (21.4%) were found to have RLS and 87 (47.8%) met at least one of the RLS diagnostic criteria. The prevalence of RLS was significantly higher in the schizophrenia group than in the control group (p=0.009), as were the RLS scores (p<0.001). The BPRS (p=0.001) and the AIS (p<0.001) scores were higher in the RLS group than in the group with no RLS symptoms. We conclude that it is important to consider the diagnosis of RLS when schizophrenic patients complain of insomnia, and that RLS symptoms could be associated with more severe psychiatric symptoms and insomnia.