The study is a preliminary investigation to compare the effectiveness of buprenorphine and methadone as opiate detoxification treatments. The sample comprised 123 drug misusers who were dependent upon opiates only or who were codependent upon opiates and benzodiazepines. Drug misusers dependent upon methadone doses up to 70 mg were eligible for the study. Detoxification took place within a specialist inpatient drug-dependence unit. Withdrawal symptom severity was assessed on a daily basis by means of the Short Opiate Withdrawal Scale. Outcome was assessed for reductions in severity of withdrawal symptoms, treatment retention, and treatment completion. Buprenorphine detoxification was associated with less severe opiate withdrawal symptoms than methadone. Opiate/Benzodiazepine codependent patients reported less severe withdrawal symptoms during treatment with buprenorphine than with methadone and were also more likely to complete detoxification when treated with buprenorphine.