BACKGROUND The advent of buprenorphine as an alternative to methadone has dramatically shifted the landscape of opioid agonist therapy (OAT) for opioid use disorder (OUD). However, there is limited US national level data describing the differences between patients who are prescribed these two OAT options. METHODS From veterans with OUD diagnosis who used Veterans Health Administration services in 2012, we identified 3 mutually exclusive groups: those who received (1) buprenorphine only (n=5,670); (2) methadone only (n=6,252); or (3) both buprenorphine and methadone in the same year (n=2513). We calculated the bi-varate effect size differences (risk ratios and Cohen's d) for characteristics that differentiated these groups. Logistic regression analysis was then used to identify factors independently differentiating the groups. RESULTS Ten year increment in age (OR 0.67; 95% CI 0.64-0.70), urban residence (OR 0.26; 95% CI 0.25-0.33), and black race (OR 0.39; 95% CI 0.35-0.43) were strongly and negatively associated with odds of receiving buprenorphine compared to methadone, while medical and psychiatric comorbidities or receipt of other psychiatric medications did not demonstrate substantial differences between groups. CONCLUSIONS Differences between veterans receiving buprenorphine or methadone based OAT seems to be largely shaped by demographic characteristics rather than medical or psychiatric or service use characteristics. A clearer understanding of the reasons for racial differences could be helpful in assuring that black OUD patients are not denied the opportunity to receive buprenorphine if that is their preference.