This study evaluated the potential economic impact of the buprenorphine/naloxone combination in the context of practice in the United States of America. In comparison to treatment provided through methadone clinics, buprenorphine/naloxone therapy in office practice may be associated with increased medication, physician, and nursing costs, but reduced costs for dispensing, toxicology screens, counseling and administration. It may also result in markedly reduced costs for patients, especially travel costs, resulting in net savings for society as a whole. A review of controlled studies suggest that buprenorphine/naloxone is not likely to be any more or less effective than methadone, but since it will be less expensive in the long run, it may be more cost-effective than methadone when provided to comparable groups of patients. Because of the convenience of office-based treatment, buprenorphine/naloxone may increase access to opiate substitution for some addicts. To the extent that treatment is provided to additional high-cost patients who are involved in extensive criminal activity or who undergo multiple detoxifications each year, net cost savings could be substantial. To the extent that treatment is extended to better adjusted addicts who are employed, married and experience fewer adverse effects from their addiction, costs could increase. The total cost impact will depend on which addict sub-populations make greatest use of the treatment opportunity presented by buprenorphine/naloxone.