BACKGROUND: The Magistrates Early Referral into Treatment (MERIT) program is a voluntary, pre-plea diversion program for defendants appearing in the New South Wales (NSW), Australia, Local Court who have issues related to their alcohol and other drug (AOD) use. METHODS: Matched treatment and comparison groups were created using propensity score matching. The outcomes examined were AOD-related hospital admissions, AOD-related Emergency Department (ED) admissions, ED admissions (general), hospital admission (general), ambulance callouts, AOD related deaths, and deaths from any cause, as well as reoffending and imprisonment. Differences between outcomes were analysed using Cox regression (health outcomes), negative binomial regression (reoffending) and logistic regression (imprisonment). RESULTS: Survival times for participants in the MERIT program were significantly shorter for all health outcomes except one (death). At the 12-month mark, MERIT participants offended 21 per cent less frequently than comparison group participants (IRR: 0.793. CI: 0.748-0.841). This gap increased to 27 per cent after 24 months (IRR: 0.870. CI: 0.829-0.912). At the conclusion of criminal proceedings participants in the MERIT program were significantly less likely to receive a prison sentence (OR: 0.728. CI: 0.674-0.787) or to die (OR: 0.674. CI: 0.502-0.904) CONCLUSION: The Magistrates' Early Referral Into Treatment Program appears to be an effective way of reducing the short-term risk of re-offending, imprisonment, and death.