This study describes on-site behavioral health treatment capacity in health centers in 2007 and examines whether capacity was associated with health center characteristics, county-level behavioral health workforce, and same-day billing restrictions. Cross-sectional data from the 2007 Area Resource File and Uniform Data System were linked with data on Medicaid same-day billing restrictions. Mental health treatment capacity was common; almost four in five health centers provided on-site mental health services. Additional services such as crisis counseling (20 %), treatment from a psychiatrist (29 %), and substance abuse treatment were offered by fewer health centers (51 % provide on-site services and only 20 % employ substance abuse specialists). In multivariate analysis, larger health centers, health centers located in counties with a larger behavioral health workforce per capita, and those located in the West and Northeast were more likely to have behavioral health capacity. Same-day billing restrictions were associated with lower odds of substance use treatment capacity and providing 24 hr crisis counseling services.