OBJECTIVE: To compare treatment retention in a Medication for Opioid Use Disorder program between older and younger adults with opioid use disorder. METHODS: This retrospective cohort study was conducted from 2015 to 2018 at an urban academic hospital's opioid and drug treatment center. Participants were adults, 18 and older, diagnosed with Opioid Type Dependence. Older adults were defined as age 50 and older. Poisson and logistic regression analyses examined whether older age was associated with treatment retention. RESULTS: Overall, 288 individual charts were reviewed; 123 were aged 18-49, and 78 were aged 50 and older. Older adults were more likely to stay in treatment for six months or longer (OR=1.73, [1.02, 2.96], P-value = 0.04] and have a higher number of treatment visits overall (RR=1.06, [0.98, 1.16] (P-value=0.16). CONCLUSIONS: Older adults are more likely than younger adults to be retained in long-term treatment in Medication for Opioid Use Disorder program. [ABSTRACT FROM AUTHOR]