BACKGROUND: Adolescence is an important period with respect to health promotion, because development of health behavior at this stage is the foundation of health in adalts. Among the social factors, family factor which affects the primary social function can be the most fundamental. We investigated the effects of father's health behavior on the health behavior of their children during adolescence. METHODS: From June to August 1999, 300 adolescent students from middle schools and high schools of areas including four cities (Seoul, Incheon, Anyang, Gunpo) and their fathers were questioned about general characteristics and health behavior such as smoking, alcohol drinking, exercise, duration of sleep, body weight, height and eating habits for breakfast ('Alameda 7'). The relationship between father's health behavior and their adolescents' health behavior was analyzed by chi-squared test. RESULTS: Among 300 adolescents and their fathers, 211 pairs responded appropriately to the questionnaires. Adolescent's smoking was not associated with father's smoking. In drinking there was no significant association between father and adolescent, but in drinking amount, father's high drinking amount was significantly associated in all students, especially in females and high school students. Regular diet, exercise, sleep did not show significant association between father and adolescent. The proportion of obesity in adolescents whose fathers were obese was significantly greater compared to those whose fathers were not. CONCLUSION: High drinking amount and obesity had a statistical significance of association between fathers and adolescents. When we consider adolescents' health behavior, their fathers' health behavior must be considered.