OBJECTIVES: Methadone maintenance programs (MMP) offer the best treatment for opioid dependence. In Spain, methadone hydrochloride is prepared as a magistral formulation. Despite the organization and the management of the MMP is in hands of the Delegación del Gobierno para el Plan Nacional sobre Drogas, each autonomous region (AR) is responsible for its planning and financing. The aim of this study was to identify planning MMP differences among AR in Spain. METHODS: A structured literature review on the IME, SciELO, Doyma, Medline, national and AR official bulletins and health web pages, and general and specialised press, up to July 1, 2010. RESULTS: Planning differences were found around four areas. First, in 13 AR the regional health department establishes the health care provision and legal framework for MMP, whereas in 4 AR this is a shared responsibility between health and social security regional departments. Second, three health care networks for the provision of MMP coexist in Spain. Andalusia has drug care centers, 6 AR specialized or mental health centers and 10 AR combine both structures. Third, in 11 AR methadone prescribing and dispensing is performed in one center, in 6 AR in separate centers and in Cantabria coincide both systems. Fourth, in the majority of AR a central laboratory or the hospitals elaborate the greater part of the methadone; however, in 2 AR it is elaborated in pharmacies and in 2 AR in the prescribing center. CONCLUSIONS: In Spain, patients are not always normalized into the health care system. Methadone provided in the MMP shows different elaboration, prescribing and dispensing processes across the different AR. This may lead to heterogeneity in the magistral formulation of methadone and patient access to it across the territory.