Objective: This study assessed the prevalence of night eating syndrome and its comorbid psychopathology in a psychiatric population. Method: The Night Eating Questionnaire was administered to 399 patients in two psychiatric outpatient clinics. Those scoring above 20 on the questionnaire (N=205) were assessed for night eating syndrome with a semistructured telephone interview. Chart reviews of all participants were performed to determine their psychiatric diagnoses and medications. Results: Forty-nine participants (12.3%) met criteria for night eating syndrome. Greater rates of substance use disorders were found among patients diagnosed with night eating syndrome than among those without the syndrome. Obese patients were more likely than nonobese patients to manifest night eating syndrome. Conclusions: Night eating syndrome is prevalent among psychiatric clinic outpatients and is likely to co-occur with substance use disorders and obesity.