The State of California is midway through a five-year effort to dramatically expand, improve, and reorganize Medi-Cal’s system for treating people with substance use disorders (SUDs). Forty California counties are taking part in the Drug Medi-Cal Organized Delivery System (DMC-ODS) pilot program under California’s Medicaid Section 1115 waiver, which was approved in 2015 and will run through 2020. This report summarizes the DMC-ODS program and the experiences of four early adopter counties — Los Angeles, Marin, Riverside, and Santa Clara — that began providing the expanded set of SUD treatment services in 2017.