In this article, we examine the impact of two universal, grade 1 preventive interventions on the onset of tobacco smoking as assessed in early adolescence. The classroom-centered (CC) intervention was designed to reduce the risk for tobacco smoking by enhancing teachers' behavior management skills in first grade and, thereby, reducing child attention problems and aggressive and shy behavior-known risk behaviors for later substance use. The family-school partnership (FSP) intervention targeted these early risk behaviors via improvements in parent-teacher communication and parents' child behavior management strategies. A cohort of 678 urban, predominately African-American, public school students were randomly assigned to one of three Grade 1 classrooms at entrance to primary school (age 6). One classroom featured the CC intervention, a second the FSP intervention, and the third served as a control classroom. Six years later, 81% of the students completed audio computer-assisted self-interviews. Relative to controls, a modest attenuation in the risk of smoking initiation was found for students who had been assigned to either the CC or FSP intervention classrooms (26% versus 33%) (adjusted relative risk for CC/control contrast=0.57, 95% confidence interval (CI), 0.34-0.96; adjusted relative risk for FSP/control contrast=0.69, 95% CI, 0.50-0.97). Results lend support to targeting the early antecedent risk behaviors for tobacco smoking.