Objective-This study examined differences in service needs and treatment utilization, retention, and outcomes between African-American, Hispanic, and white substance abusers in communitybased treatment programs.Methods-Data were collected from 2,401 African Americans, 3,222 Hispanics, and 7,980 whites who were admitted to 43 drug treatment programs across California from 2000 to 2001. The Addiction Severity Index (ASI) was administered at intake to assess clients' problem severity in a number of domains (alcohol use, drug use, employment, family and social relationships, legal, medical, and psychological), and treatment retention and arrest data were obtained from administrative records. A subsample was followed up at three months to assess service utilization (N=2,145) and again at nine months to readminister the ASI (N=2,566).Results-All three groups had similar severity levels of drug and legal problems upon treatment entry. Upon entry to treatment, white clients had the highest severity levels of alcohol, family, and psychiatric problems and African Americans had the highest severity levels of employment problems compared with the other two groups. Treatment retention did not differ between the three groups, but whites received a greater number of alcohol treatment services than did African Americans or Hispanics, and African Americans received a greater number of employment services than did Hispanic and white clients. All three groups showed significant improvement in all outcome domains except for medical outcomes. At the nine-month follow-up, whites had worse outcomes in the alcohol domain compared with the other two groups, and whites had worse outcomes in the legal domain compared with Hispanics. Compared with whites, African Americans were significantly less likely to be charged with driving under the influence in the year after treatment admission.Conclusions-All three groups improved after treatment, although benefits from treatment can be further enhanced if services underscore different facets of the psychosocial problems of each racial and ethnic group.Racial and ethnic disparities in the availability and quality of substance abuse treatment are of interest to both policy makers and treatment service providers. A number of studies have indicated greater unmet needs for health services and poorer health outcomes for persons from racial or ethnic minority groups across a range of disease areas, including cardiovascular disease, mental disorders, diabetes, and other chronic and infectious diseases (1). However, there has been little research on the service needs, utilization, and outcomes of African Americans and Hispanics in substance abuse treatment.The authors report no competing interests. Few studies have examined the service needs of persons from racial or ethnic minority groups in substance abuse treatment. Some studies have indicated that among persons in drug treatment, Hispanics have more severe substance use (2) and employment problems (2,3) than do African Americans or whites. Le...