Individuals with co-occurring serious mental illness and substance use disorders experience a highly fragmented system of care, contributing to poor health outcomes and elevated levels of unmet treatment needs. Several elements in the health care reform law may address these issues by enhancing the integration of physical and behavioral health care systems. The purpose of this paper is to analyze these elements, which fall into three domains: increasing access, restructuring financing and reimbursement mechanisms, and enhancing infrastructure. We conclude with a consideration of the implementation challenges that lie ahead.