BackgroundIndividuals who have substance use disorders may have an elevated risk of suicidality. This study sought to examine the prevalence of, and identify factors associated with, suicidality in adults with opioid use disorder (OUD) initiating office-based buprenorphine treatment.MethodsIndividuals were eligible to participate if they had OUD and had initiated treatment in the past month. Participants (n= 244) completed a semi-structured interview using the Addiction Severity Index—Lite.ResultsAt baseline, 37.70% of participants reported significant thoughts of suicide over their lifetime and 27.46% reported suicidal attempts over their lifetime. Logistic regression analyses were used to identify predictors of lifetime suicidal thoughts and attempts. A history of physical abuse (OR = 4.31,p< .001), having chronic pain-related conditions (OR = 3.28,p< .001), a history of depression (OR = 3.30,p= .001) or anxiety (OR = 7.47,p= .001), and Latino/a/x ethnicity (OR = 2.66,p= .01) were associated with an increased risk of lifetime suicidal thoughts. A history of sexual abuse (OR = 2.89,p= .01), Latino/a/x ethnicity (OR = 4.01,p< .001), a history of depression (OR = 4.03,p= .001) or anxiety (OR = 15.65,p= .007) and having a chronic pain-related condition (OR = 2.43,p= .01), were associated with an increased risk of lifetime suicide attempts.ConclusionsResults demonstrate the high prevalence of suicidal thoughts and attempts among patients initiating buprenorphine. Findings may help to better identify at-risk patients and to inform screening, prevention, and mental health treatment efforts.Trial registration: ClinicalTrials.gov, NCT04650386 (registered 12 December 2020,https://clinicaltrials.gov/ct2/show/NCT04650386) and NCT04257214 (registered 5 February 2020,https://clinicaltrials.gov/ct2/show/NCT04257214).