This study examined initiation into drug use during grade school years in a sample of Cuban-American, Black, and White non-Hispanic students in the greater Miami, Fla, area. Findings indicate that first use of alcohol occurs in fifth grade and cigarettes in sixth grade for all subgroups except White non-Hispanics, who peak in the fifth grade. White non-Hispanics had the highest life-time levels of alcohol and cigarette use. Foreign-born Cuban Americans had a lower lifetime prevalence of alcohol and cigarette use than US-born Cuban Americans. Higher acculturation level was related to first use of alcohol. One important implication of this study is that alcohol interventions should begin no later than third grade and smoking interventions no later than fourth grade.