Clinicians have often observed that Asians are unlikely to utilize substance-dependence treatment services but few have reported empirical data examining this phenomenon. This study used data from the National Household Survey on Drug Abuse, 2000-2002, and tested whether Asians in the United States have relatively low rates of drug and alcohol dependence and whether substance-dependent Asians use treatment services less than Caucasians. Subsequent analyses were undertaken to identify factors that explained these racial differences. Of the 5,118 Asians, 159 met criteria for past-year drug or alcohol dependence. Asians with past-year substance dependence were significantly less likely than substance-dependent Caucasians to report past-year treatment (odds ratio 0.42, 95% confidence interval 0.19-0.96). Differences in past-year substance-dependence prevalence appear to be partially explained by between-group differences in ever using substances; differences in past-year treatment use appear to be in part related to differences in levels of acculturation and education.