Adolescent substance abuse potentially holds a number of negative implications for the health and well-being of the individual, including increased risk for injury and death from interpersonal violence, motor vehicle accidents, and drowning, increased probability of engaging in high risk sexual behaviors; and increased risk for suicidal ideation and behaviors. The aim of this paper is to estimate prevalence of substance abuse among the sample of 10th grade male students in Tabriz City, and to evaluate the associated factors. Of all 10th grade male students in Tabriz, Iran, 1785(13.7%) were randomly sampled. Mean age of the subjects was 16.3+/-0.87 years. A self-administered questionnaire was used to collect demographic data, substance abuse, smoking status and friends smoking. The influence of different factors on substance abuse was evaluated with a logistic regression model. Among 1785 students 226 (12.7%, 95% CI: 11.2-14.3) had ever used alcohol and 36 (2.0%, 95% CI: 1.5-2.8) had used drugs. The results indicate that older age (OR=1.55), having general risk taking behavior (OR=1.70), higher smoking stage (OR=3.70), having self-injury (OR=1.22), higher socioeconomic class (OR=1.62), and ever use of illicit drugs (OR=5.72) were factors associated with student's ever use of alcohol. This study has shown low prevalence of substance abuse and determined some of its risk factors among students. More studies about adolescent population are necessary to approve the observed results of this study and thus allow for a certain generalization of the observations.