Most substance abuse treatment occurs in outpatient treatment centers, necessitating an understanding of what motivates organizations to adopt new treatment modalities. Tichy's framework of organizations as being comprised of three intertwined internal systems (technical, cultural, and political) was used to explain treatment organizations' slow adoption of buprenorphine, a new medication for opiate dependence. Primary data were collected from substance abuse treatment organizations in four of the ten metropolitan areas with the largest number of heroin users. Only about one fifth offered buprenorphine. All three internal systems were important determinants of buprenorphine adoption in our multivariate model. However, the cultural system, measured by attitude toward medications, was a necessary condition for adoption. Health policies designed to encourage adoption of evidence-based performance measures typically focus on the technical system of organizations. These findings suggest that such policies would be more effective if they incorporate an understanding of all three internal systems.