OBJECTIVES: To establish an accurate estimate of the prevalence of smoking among high school students in Aleppo-Syria and to characterize the smoking habit in this age group. DESIGN: A cross-sectional survey was performed, in which a self-administered questionnaire was distributed to 10th, 11th and 12th graders. SUBJECTS: A sample of 1587 students (784 males; mean age 16 years, and 803 females; mean age 15.9 years) was studied. This sample was drawn from 16 schools randomly selected from a total of 73 schools in the city. RESULTS: The prevalence of current smoking was 15.9% for males and 6.6% for females. The prevalence of daily smoking was 2.4% for males and 0.5% for females. Almost all smoking categories increased with age and grade. Forty seven percent of male daily smokers were heavy smokers. Peer influence was evident in all stages of the smoking process, especially for males. Parental smoking was also an important associated factor. The combination of parental and siblings smoking was the strongest predictor of the smoking status of the surveyed (OR: 4.4; 95% CI: 2.7-7). Thirty eight percent of male smokers and 47.2% of female smokers smoke out of boredom. Fifty one percent of male smokers were introduced to smoking by a friend. Forty percent of male smokers buy their cigarettes, while 56.6% of female smokers obtain their cigarettes from home. Logistic regression analyses showed that parental and siblings smoking were the most important predictors of ever trying to smoke or current smoking among male and female students. CONCLUSIONS: Our study shows that smoking is more frequent in male than female students. Parental and sibling smoking are the most important factors associated with smoking in this population, and peer influence is important particularly in the smoking-initiation stage. Pattern of smoking and associated factors differed substantially between males and females in this study.