Tarzana Treatment Centers, Inc. (TTC) will expand access to medications for addiction treatment (MAT) and improve outcomes for individuals with opioid use disorder (OUD) in Los Angeles County (LAC), which experienced a 117% increase in fentanyl overdose deaths during the first 5 months of the pandemic. The population of focus for TTC’s MAT-Expansion Project will be adults ages 18+, especially vulnerable populations such as individuals being released from jail/prison, persons experiencing homelessness, and individuals exiting publicly funded inpatient detoxification. In 2020, TTC provided treatment for 1,805 unduplicated OUD patients. The majority were White (53%) or Latino (36%) males (74%) ages 18-40 (73%) whose primary drug was heroin (71%). Nearly three quarters (73%) were referred to TTC via LAC’s publicly funded Drug Medi-Cal Organized Delivery System (DMC-ODS). More than half (58%) were enrolled in inpatient detox, 9% in residential rehabilitation, and 31% in outpatient treatment with an average length of stay of 51 days. Approximately 20% of all TTC’s OUD patients were engaged in MAT services (up from 6% in 2018). More than 175,000 individuals in LAC are estimated to have an OUD (2% prevalence), but only about 18% were receiving treatment in 2019. TTC has been implementing the SAMHSA-funded MAT-Expansion Project since 2018. Although the project has met enrollment targets, follow-up rates have been low (52% for 3-month; 27% for 6-month). While length of stay was longer for MAT-Expansion Project participants at 160 days, TTC had difficulty reaching patients to schedule follow-ups due to losing contact after discharge. TTC’s proposed project will address identified service gaps and increased OUD prevalence in LAC by providing project participants with evidence-based MAT services (buprenorphine products, methadone, and naltrexone), co-occurring mental health services, recovery support services, and other critical services (primary medical care, HIV and Hepatitis C specialty care and prevention services, case management, etc.) offered through TTC’s integrated care model at substance use disorder (SUD) treatment facilities and co-located Opioid Treatment Program (OTP) facilities in the San Ferando and Antelope Valleys. In addition, TTC will conduct the following activities: 1) targeted outreach and virtual MAT trainings with local community-based organizations working with reentry and other vulnerable populations such as the homeless and LGBTQ+, and with primary care, mental health, and social service providers; 2) MAT trainings with TTC’s SUD counselors and other treatment staff; 3) MAT educational groups with OUD patients at TTC’s inpatient detox and other treatment programs; and 4) weekly MAT support groups for participants. TTC will serve a minimum of 150 individuals in Year 1 and 180 annually in Years 2-5 for a total of 870 unduplicated individuals served during the five-year project period. Key outcomes include an increase in the overall proportion of OUD patients who are enrolled in MAT services, increased treatment retention, increased abstinence from illicit drug use (including prescription opioid misuse), decreased involvement in the criminal justice system, and increased social connectedness.