Objective: To assess prevalence and predictors of hepatitis B immune status among adolescents and young adults (AYA) seeking outpatient medication treatment for opioid use disorder (MOUD).Study Design: A retrospective medical chart review was conducted of AYA seeking MOUD between January 1, 2013 through December 31, 2015. Inclusion criteria included: diagnosis of opioid use disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; received hepatitis serologic testing; and no evidence of prior or current hepatitis B infection.