Some studies report differences in opioid withdrawal between racial/ethnic groups. However, it is not known if these differences are reflected in differential treatment response. Data from National Institute on Drug Abuse (NIDA) Clinical Trials Network-003 were used to examine racial/ethnic differences before and during stabilization with buprenorphine. At induction, non-Hispanic Caucasians had higher objective and subjective withdrawal scores and greater opioid craving than minority participants. No significant between-group differences were observed on these scales following buprenorphine. Non-Hispanic Caucasians and Hispanics reported more adverse events than African Americans. Although ethnic and racial differences were observed prior to buprenorphine treatment, scores following buprenorphine treatment were similar between groups.