This study examined the prevalence and correlates of alcohol, tobacco, and drug use among military recruits prior to enlistment. As part of a 5-year longitudinal study, a baseline survey was conducted with 2,002 Naval recruits. Despite being overwhelmingly underage, 75% of recruits consumed alcohol in the year before enlistment, and 26% had engaged in heavy drinking. About half had used tobacco, and 31% had used drugs. Multivariate logistic regression analysis revealed that although men were not at significantly greater risk than were women for preenlistment alcohol, heavy drinking or drug use, they were at elevated risk for preenlistment tobacco use (Odds Ratio D 1.71; 95% Confidence Interval D 1.21, 2.41). Normative beliefs concerning best friend’s drinking were highly predictive of each outcome. Prior use of each substance was significantly associated with prior use of other substances. Preenlistment drinking, smoking, and drug use are prevalent behaviors in this population. These data can help to heighten awareness among employers as to the prevalence of substance use in the 17–24-year-old age group, and thereby inform policy and prevention programs.