This study was conducted to examine the effect of family environment on smoking behavior, smoking knowledge and smoking attitude in primary school students. For the purpose of the study, a questionnaire-based examination was made with 1,476 sixth-grade students in Taegu from November 1st to 30th, 1998. The results of the study are summarized as follows. Out of 22 points for smoking knowledge, the male student group got 12.9 points, and the female student group 13.0 points. For both groups, students with better school achievement showed a significantly higher score (p<0.01). For the female student group, those who had nonsmoking fathers showed a significantly higher score(p<0.05). A perfect score for smoking attitude was 20 points. The male student group received 14.9 points and the female student group 16.3. For both groups, the score appeared to be significantly higher in the students who had better school achievement and no smoking experience. For the female group, the score was higher if they were living with widowed mothers or had nonsmoking parents. The percentage of smoking experience was 22.0% for the male group and 4.7% for the female group. The present smoking percentage of both groups accounted for 0.3% and 0.1%, respectively. The percentage of the male group's smoking experience was significantly higher if school achievement was poor, if the mother has religious, and if her occupation belonged to significantly different category. For the female group, it was significantly higher if a mother's educational background was less than the primary school level, or if a mother smokes. Family adaptability and cohesion were not significant variables for both groups. The score for smoking knowledge according to family cohesion was highest if male and female members were in an enmeshed state. For the female group, the higher the family adaptability, the significantly higher the score for smoking knowledge. The score for smoking attitude according to family cohesion showed a significant difference for both groups. The family adaptability was not a significant variable for both groups. The results of multiple regression analysis, with the scores for smoking knowledge and smoking attitude were used as a dependent variable, revealed that, for both groups, the better the school achievement. For the female group, the higher the family cohesion, the significantly higher the score(p<0.01). For the male group, the score for smoking attitude was significant1y higher if school achievement was better, if students were living with a widowed mother or father, if they had drinking mothers, if family adaptability was low, if family cohesion was high, or if the score for smoking knowledge was high. For the female group, the score for smoking attitude was higher if school achievement was better. Also, if famale student had nonsmoking fathers, if the family adaptability was lower, on the higher the score for smoking knowledge, a smoking attitude scored higher. The results of a multiple logistic analysis, with smoking experience as a dependent variable, revealed that, for the male student group, the worse the school achievement, the higher the score for smoking knowledge, the lower the score for smoking attitude, or the lower the family adaptability, the higher the percentage of smoking experience. For the female student group, the higher the score for smoking knowledge or the lower the score for smoking attitude, the higher the percentage of smoking experience. In conclusion, family environment, including smoking of parents and family functions, had a great effect on smoking knowledge, smoking attitude and smoking experience of students, and it is required to adjust subjects and methods for smoking and nonsmoking education as smoking attitude and smoking behavior greatly differ according to sex.