Court drug diversion programs are now available in all jurisdictions in Australia, but there is increasing evidence that such programs have differing success rates for certain client populations, including indigenous clients. This study investigates client characteristics, program completion rates and factors associated with retention, for all 484 clients admitted to the Northern Territory's Court Referral and Evaluation for Drug Intervention and Treatment 12 week illicit drug pre-sentence court diversion program between July 2003 and December 2008. Client data were collected by court clinicians as part of the face-to-face assessment interview and treatment outcomes were recorded. Multivariate logistic regression analysis showed that indigenous clients were significantly less likely to complete their treatment than non-indigenous clients, as were clients who were younger, male, had an educational level of Year 10 or less, were unemployed, had a previous custodial order and used drugs other than cannabis. The lower program completion rates for indigenous clients are consistent with findings from other Australian studies and highlight the need to further explore and address factors contributing to this result.