AIMS: To determine the efficacy of Opiate Maintenance Therapy (OMT) and adjunctive interventions for dual heroin and cocaine dependence by means of a meta-analysis. METHOD: We searched for and retrieved randomized controlled clinical trials. We used RevMan 5.0 with random effects modeling for statistical analysis and for comparisons of relative risk, effect sizes, and confidence intervals. Subsequent moderator variables and sensitivity analyses were performed. RESULTS: Thirty-seven studies, which have enrolled 3,029 patients, have been included in this meta-analysis. High doses of OMT were more efficacious than lower ones in the achievement of sustained heroin abstinence (RR = 2.24 [1.54, 3.24], p < .0001) but had no effect on cocaine abstinence. At equivalent doses, methadone was more efficacious than buprenorphine on cocaine abstinence (RR = 1.63 [1.20, 2.22], p = .002) and also appeared to be superior on heroin abstinence (RR = 1.39 [1.00, 1.93], p = .05). Several pharmacological and psychological potentiation strategies have been investigated. An improvement on sustained cocaine abstinence was achieved with indirect dopaminergic agonists (RR = 1.44 [1.05, 1.98], p = .03) and with contingency management (CM) focusing on cocaine abstinence (RR = 3.11 [1.80, 5.35], p < .0001). CONCLUSIONS: Dual opioid and cocaine dependence can be effectively treated with OMT in combination with adjunctive interventions. Higher OMT doses are preferable to lower ones and methadone to buprenorphine. OMT can be enhanced with indirect dopaminergic drugs and with CM focusing on cocaine abstinence.