Methadone and buprenorphine/naloxone are the two recommended pharmacotherapies for the treatment of opioid dependence, having been demonstrated to be effective in numerous clinical trials. While methadone has been an approved treatment for opioid dependence for that past 50 years, buprenorphine/naloxone is a newer substance that was only approved for use in 2002. This mixed-methods study utilizes a comprehensive conceptual framework of neoinstitutional theory and institutional logics to explore possible factors that might predict adoption of medication-assisted treatment. First, in-depth qualitative interviews with managerial level staff at substance abuse treatment centers were conducted. The interviews were semi-structured and explored perceptions of treatment philosophy, the merging of substance abuse and mental health, managed care, services, funding, licensing and accreditation and personal and professional networks. Next, logistic regression models were used to explore possible predictors of medication-assisted treatment. The National Treatment Center Study (NTCS), a nationally representative survey of private substance abuse treatment facilities conducted between 2002-2004, was used in this study, allowing for the exploration of early adoption of buprenorphine/naloxone. Findings from the qualitative interviews suggested that the two medications are viewed differently and should therefore be explored separately. Findings from the logistic analysis of the NTCS supported this distinction. The proportion of clients with a primary diagnosis of opiate dependence or abuse was the only factor positively associated with both the early adoption of buprenorphine/naloxone and methadone provision. The program's proportion of managed care funding was the only other significant predictor for early adoption of buprenorphine/naloxone. Accreditation by JACHO, proportion of clients who are women and past organizational participation in research, all positively predicted methadone provision, while the proportion of counselors with a master's degree or higher negatively predicted it. The results indicate that coercive and normative institutional forces, as well as the institutional logics operating on organizations and the organizational networks they are embedded in, impact service provision and adoption of innovation. To promote adoption of pharmacotherapies into treatment, attention must be paid to the unique barriers and opportunities facing the adoption of each medication.