OBJECTIVE: Although depression is one of the most common problems of medical and psychiatric outpatients, it has not been clear whether the extent of medical comorbidity among depressed patients varies across major types of clinical settings in which depressed patients receive care--especially by type of treating clinician (general medical versus mental health specialty) or type of payment for services (prepaid versus fee-for-service). METHODS: The authors examined these issues using data on 1,152 adult outpatients with current depressive symptoms and a lifetime history of unipolar depressive disorder who received care in one of three health care delivery systems in three U.S. sites. RESULTS: Depressed patients had a similarly high prevalence (64.9%- 71.0%) of any of eight common chronic medical conditions whether they were seen in the general medical or specialty mental health sector; however, those visiting medical clinicians had a significantly higher prevalence of the two most common chronic medical conditions, hypertension and arthritis. Among depressed patients with hypertension, those visiting the general medical sector were more likely to be taking antihypertensive medication than were those visiting the mental health specialty sector. Type of payment (prepaid versus fee-for-service) was unrelated to either prevalence or severity of comorbid medical conditions, suggesting that the typical depressed patient in all types of practices studied had medical comorbidity. CONCLUSIONS: These data suggest that clinicians in all health care settings must be prepared to encounter chronic medical conditions and complaints in the depressed patients who visit them.Abstract Teaser