Cigarette smoking is one of the most important and the most preventable causes of mortality. There is an increasing tendency towards smoking among the young and adolescents. This study was performed on 206 male students in 6 colleges of Yasuj University of Medical Sciences. Results of this study showed that 78.2 %( out of all the subjects) are non-smokers, 15.6% smoke only cigarettes, 1.5% smoke, cigarettes and pipe, 2.9% smoke cigarettes and water pipe, 0.9% smoke cigarettes, pipe and water pipe and 0.9% only smoke water pipe. It was observed that 11.6% of the students had been smoking in the past, 69.8% smoke occasionally and 18.6% are regular smokers. Factors such as the psychological and emotional environment of the family, religious beliefs and practices and having a smoker in the family, were significantly different among the smokers as compared to non - smokers. On the other hand, the differences were not significant for age group, marriage, type of college, birth place, and living place. The most important reasons for smoking (for the first time) were found to be curiosity (30%), having a smoker friend (20.9%) and psychological and emotional problems (25.6%). 76.3% of smoker students (29 students) expressed their desire to cease smoking and health problems were their main concern.