Despite high rates of psychiatric morbidity among young offenders, few studies look closely at prevalence rates in terms of race/ethnicity or developmental stage. Seven hundred and ninety (790) incarcerated young people with a mean age of 18±1.2 years were examined. The racial/ethnic distribution was White (17%), African American (28%), Hispanic (47%) and Other (8%). White males had greater than average levels of psychosis; African American males showed lower than average alcohol dependence rates but higher levels of marijuana dependence. White females were more likely than Hispanic and African American females to have attention deficit-hyperactivity disorder and substance and stimulant dependence. Race/ethnicity and age differences can be useful when creating culturally-informed and developmentally appropriate interventions for incarcerated young people.