Objectives. We examined the associations among early-adolescent substance use, subsequent young-adult substance use disorders, and psychiatric disorders among a community sample of males. Methods. Early-adolescent data were collected in classroom surveys (1990–1993), and young-adult data were collected in face-to-face interviews (1998–2000). Results. We found strong associations between early-adolescent substance use and young-adult substance use disorders and psychiatric disorders. The magnitudes of these associations varied by racial/ethnic group and were strongest among African Americans and foreign-born Hispanics, who reported the lowest early-adolescent substance use. Conclusions. Early-adolescent substance use is most strongly associated with a later pattern of dysfunction among the racial/ethnic groups that reported the lowest levels of early use. The implications of our findings in the context of primary and secondary prevention are discussed.