OBJECTIVE: This study tested the validity in the adult general population of the Mood Disorder Questionnaire, a screening instrument for bipolar I and II disorders. The Mood Disorder Questionnaire has been validated in a psychiatric outpatient study group. METHOD: A total of 711 subjects (stratified by Mood Disorder Questionnaire score) were randomly selected from a group of 85,358 adult respondents in a nationwide epidemiological general population sample that was balanced for key demographic variables. Of these, 695 subjects received a telephone interview involving an abbreviated version of the Structured Clinical Interview for DSM-IV. RESULTS: A sensitivity of 0.281 and a specificity of 0.972 were obtained for the Mood Disorder Questionnaire. CONCLUSIONS: The Mood Disorder Questionnaire is a useful screening instrument for bipolar I and II disorders in the community. The operating characteristics of the Mood Disorder Questionnaire in the general population differ substantially from its characteristics in outpatient psychiatric settings.