This article investigates the effective factors in male pre- university students' tendency toward drug abuse on the basis of the viewpoints of students, law executors, and educational experts in the city of Tehran. Participants were selected through random staged sampling method and the formula of sample volume determination. They consist of 600 persons: 40 law executors, 60 educational experts, and 500 pre-university students. A questionnaire containing 277 questions was administered to the sample and was analyzed based on the statistical test of factor analysis. The findings show that 18independent variables have direct impact on the dependent variable, namely, tendency to drug abuse: adolescence, genetics, personal characteristics, mental disorders, positive attitudes toward drugs, dangerous situations, drug impact on person, family, friends, school, living place, rules, drug market, drug abusing as a social norm, lack of alternative activities, lack of consulting opportunities, and industrial development. In general, these variables account for 46% of the variation of students' tendency to drug abuse. The findings of this research are in line with earlier researches.