This study analyzed the National Epidemiological Survey on Alcohol and Related Conditions data, 2001-2002, to compare the prevalence and odds of DSM-IV mood, anxiety, and substance use disorders and mental health service use across Asian American subethnic groups (648 East Asians, 485 Southeast Asians, 298 South Asians). Asian American subethnic groups varied in lifetime prevalence of psychiatric disorders (p=0.004), mainly due to differences in the presence of any substance use disorder (p=0.06), and specifically, drug use disorders (p=0.02). While Southeast Asians had the highest prevalence of substance use disorders (16.7%), fewer Southeast Asians with substance use disorders used mental health services (11.1%) compared to South Asians with substance use disorders (24.2%). East Asians compared to South Asians had significantly lower odds of mental health service use for substance use disorders (confidence interval=0.08-0.84). Asian American subethnic groups vary in the prevalence of mental disorders and in mental health service use, especially for substance use disorders.