Buprenorphine, a partial mu-opioid agonist, has been shown effective for treatment of opioid dependence but also has some abuse potential. A novel formulation of buprenorphine, using a polymer microcapsule depot sustained-release technology, has been developed which may offer effective treatment of opioid dependence while also minimizing risks of patient noncompliance and illicit diversion. This open-label, first-in-human study evaluated the safety and pharmacokinetics of a single-dose buprenorphine depot in physically dependent opioid abusers. The present study also examined the efficacy of depot buprenorphine in suppressing symptoms of opioid withdrawal, attenuating the effects of exogenous opioid challenge, and providing clinical detoxification. Five opioid-dependent volunteers each received a single subcutaneous depot injection containing 58 mg of buprenorphine and were assessed for at least four weeks for signs and symptoms of opioid withdrawal, first residentially and then as outpatients. Depot buprenorphine appeared to provide effective relief from opioid withdrawal, with no participant requiring additional medication for withdrawal relief following depot administration. The depot was safe and well-tolerated, with no significant side effects, signs of intoxication, or respiratory depression. In the opioid challenge sessions, depot buprenorphine appeared to produce substantial opioid blockade that persisted for 6 weeks post-depot administration. Results from the present study suggest that depot buprenorphine offers significant promise for enhancing the delivery of effective opioid agonist treatment while minimizing risk for abuse of the medication.