OBJECTIVE This evaluation assessed the opinions and experiences of primary care providers and their support staff before and after implementation of expanded on-site mental health services and related system changes in a primary care clinic. METHODS Individual semistructured interviews, which contained a combination of open-ended questions and rating scales, were used to elicit opinions about mental health services before on-site system and resource changes occurred and repeated following changes that were intended to improve access to on-site mental health care. RESULTS In the first set of interviews, prior to expanding mental health services, primary care providers and support staff were generally dissatisfied with the availability and scheduling of on-site mental health care. Patients were often referred outside the primary care clinic for mental health treatment, to the detriment of communication and coordinated care. Follow-up interviews conducted after expansion of mental health services, scheduling refinements and other system changes revealed improved provider satisfaction in treatment access and coordination of care. Providers appreciated immediate and on-site social worker availability to triage mental health needs and help access care, and on-site treatment was viewed as important for remaining informed about patient care the primary care providers are not delivering directly. CONCLUSIONS Expanding integrated mental health services resulted in increased staff and provider satisfaction. Our evaluation identified key components of satisfaction, including on-site collaboration and assistance triaging patient needs. The sustainability of integrated models of care requires additional study.