In 2015, the California Health Care Foundation (CHCF) launched a pilot project to develop sustainable, integrated care models to provide mental health care and substance use disorder treatment with health care for patients with opioid use disorder (OUD) in the primary care setting using medication-assisted treatment (MAT). Ten community health centers and county-run safety net clinics in California implemented initiatives with technical assistance from the Camden Coalition of Healthcare Providers. Researchers from the Urban Institute evaluated of the implementation phase of the initiative. This initiative demonstrated that it takes time, funding, technical assistance, training, leadership, and effort to help community health centers provide integrated MAT care, but that such efforts can be successful and help expand access to treatment for OUD.