We draw upon and integrate two organizational theory perspectives to develop a conceptual model of how managed care influences the treatment practices of outpatient drug treatment providers. First, using resource dependence theory, we suggest that treatment practices will vary as a function of an organization's dependence on managed care and the scope and stringency of oversight mechanisms used by managed care firms. Second, we apply institutional theory to suggest that the expectations of the professional staff and sources of legitimacy will also directly influence treatment practices. Finally, we draw upon previous integrative frameworks and argue that institutional factors will also indirectly influence treatment by moderating the negative effects of managed care dependence and oversight. © 2001.