Background: The numbers of incarcerated people suffering from drug dependence has steadily risen since the 1980s and only a small proportion of these receive appropriate treatment. A systematic review to evaluate the effectiveness and economic evidence of non-pharmacological interventions for drug using offenders was conducted. Methods: Cochrane Collaboration criteria were used to identify trials across 14 databases between 2004 and 2014. A series of meta-analyses and an economic appraisal were conducted. Results: 43 trials were identified showing to have limited effect in reducing re-arrests RR 0.97 (95% CI 0.89–1.07) and drug use RR 0.90 (95% CI 0.80–1.00) but were found to significantly reduce re-incarceration RR 0.70 (95% CI 0.57–0.85). Therapeutic community programs were found to significantly reduce the number of re-arrests RR 0.70 (95% CI 0.56–0.87). 10 papers contained economic information. One paper presented a cost-benefit analysis and two reported on the cost and cost effectiveness of the intervention. Conclusions: We suggest that therapeutic community interventions have some benefit in reducing subsequent re-arrest. We recommend that economic evaluations should form part of standard trial protocols.