Interventions designed to prevent drug abuse have typically focused on the gateway drugs of tobacco, alcohol, and marijuana, on the assumption that such prevention would indirectly prevent use of harder substances. Little data has been available, however, for examining the onset of harder substance use in a normal adolescent population. This study, based on two waves of data collected as part of Project SMART (Self Management and Resistance Training), examined the prospective prediction of harder drug use. Questionnaires on hard drug use were completed by ninth graders (N=1,450) in the 1985 school year who had completed soft drug use and psychosocial questionnaires one year earlier. The results identified top predictors of use of each hard drug examined (cocaine, heroin, lysergic acid diethylamide, stimulants, sedatives) as being: (1) use of marijuana; (2) intention to use soft drugs (cigarettes, alcohol, marijuana) if offered; (3) use of cigarettes; and (4) use of alcohol. These findings support the model that soft drug use precedes hard drug use. Risk-taking/rebelliousness showed a strong correlation across all the hard drugs. Overall prior soft drug use, friends' use, and availability of soft drugs were highly correlated with hard drug use. Intent to use soft drugs if offered, belief in the positive consequences of soft drug use, and risk-taking/rebelliousness were psychosocial variables that related to all hard drugs studied. (NB)