BACKGROUND: Recently in Korea, the rate of addictive drug abuse is rapidly increasing in men on salary, housewives, and even in adolescents, who have been considered to be free from drugs, which presents a serious problem to the society. Especially, the habituation to gateway drug, such as cigarettes and alcohol, before 15 years old, would lead to the increased possibility of other drug abuse, including illicit drugs. Thereupon in this study, we intended toreview the effect of adolescents smoking an the drug abuse and deviated behaviors. METHODS: On September, 1997, randomly selected were 12 classes, an the basis of 2 classes per grade, from the two schools which was located each in Seoul and Buchean. And survey was dane on 610 students with non non-nominl, self-reported questionnaire. RESULTS: The rate of adolescent smoking was 28.1% in male students and had increasing tendency of "the higher the grades, the higher the smoking rate"(17.0% in the 1st gade, 31.5% in the 2nd grade, 35.9% in the 3rd grade). The smoking rate of female students was 12.3%. From the 2nd grade of middle school to the 2nd grade of high school was the critical period when the smoking habit was initiated in almost 90% of the students. The experiencing rates of drug abuse in studied subjects were as follows : drinking(79.0%), stimulants(4.8%), sedatives(4.1%), hypnotics(3.1%), glue sniffing(1.5%), butane gas(0.7%), marijuana/hemp(0.2%). They were higher in the smoking group than in the nansMoking group, showing statistical significances in most items except hypnotics and marijuana/hemp. Also simihr results were shown in deviated behaviors between the groups. CONCLUSIONS: With the concerted efforts of family, school, society and natian, we as family physicians should make efforts to delay and prevent adolescent's smoking, which is a gateway to drug abuse and deviated behaviors, and to increase people's recognition of health risks caused by smoking, and to provide proper program for adolescents to stop smoking.