The study presents findings on lifetime, past year, and magnitude of use of cigarettes, alcohol and illicit drugs among non-Hispanic White (NHW), African-American, Cuban, Nicaraguan, Colombian and Puerto Rican adolescent boys. Significant increases in lifetime use and magnitude of use of all three substances were found over three data collection periods for all six groups. NHW and Hispanic adolescents had higher substance use rates than African-Americans. Most differences were not significant for NHW and Hispanic subgroups. Foreign-born Hispanics had positive relationships between length of time in country and substance use. Length of time in country was related to lifetime use of all substances for Cubans and for past year use of alcohol and illicit drugs. It was also significantly related to lifetime and past year use of alcohol and for lifetime illicit drug use among Nicaraguans. Tables, notes, references, appendix