Buprenorphine and methadone are both effective for the control of the acute signs and symptoms of opiate withdrawal, but it is not known if there are differences between these two medications for other important clinical outcomes. This observational, non-randomized study evaluated completion rates of patients over a 13-month period when buprenorphine replaced methadone as the medication used for short-term inpatient opiate detoxification. Of the 644 patients in the study, the 303 treated with buprenorphine were more likely to complete detoxification than the 341 treated with methadone (89% vs. 78%; P < .001). Improvement in completion rates coincided with the introduction of buprenorphine. We conclude that as compared to methadone, buprenorphine is associated with greater rates of completion of inpatient detoxification.