Racial and ethnic disparities in the treatment of addiction have been acknowledged for several years, yet little is known about which empirically supported treatments for substance use disorders are more or less effective in treating racial and ethnic minority clients. The current study was a secondary analysis of a randomized clinical trial of two evidence-based treatments, mindfulness-based relapse prevention (MBRP) and relapse prevention (RP), as part of a residential addiction treatment program for women referred by the criminal justice system (n = 70). At 15-week follow-up, regression analyses found that racial and ethnic minority women in MBRP, compared to non-Hispanic and racial and ethnic minority women in RP, reported significantly fewer drug use days (d = .31) and lower addiction severity (d = .65), based on the Addiction Severity Index. Although the small sample size is a limitation, the results suggest that MBRP may be more efficacious than traditional treatments for racial and ethnic minority women.