The Magistrates Early Referral into Treatment (MERIT) program is a New South Wales court-based scheme targeting adult defendants appearing before a participating Local Court who have a demonstrable illicit drug problem, and who are motivated to participate in drug treatment and rehabilitation. It diverts adult defendants with primary drug problems on bail from Local Court to a three-month intensive drug treatment program. This report examines access to, and participation in, MERIT by Aboriginal defendants. The study population consisted of 6219 persons referred to MERIT between 2 July 2000 and 31 October 2004. Of these persons, 13.7% (853) identified themselves as Aboriginal and/or Torres Strait Islander. The findings suggest that Aboriginal participants are referred to MERIT at a rate equal to or at times better than non-Aboriginal participants. However, Aboriginal participants are less likely to be accepted and are less likely to complete the program than non-Aboriginal participants. Differences in the nature of referrals, acceptances, completions, and, individual characteristics provide potential explanations for the findings. Factors highlighted as affecting the participation of Aboriginal defendants include differences between regions, between referral sources, in rates of offending while on the program, and particular treatment plans.