Especially, the teenage period, an important lifetime to develop both physically and mentally, needs to be helpful to promote the growth of the body and to keep a well-balanced mind through a balanced and nourishing diet. It is well known that the western style fast food is the most liked meal by teenagers. Wrong recognition about fast food and its frequent intake by adolescents can lead to unbalanced diet and food behaviors which may also connect with a poor impact on their personalities as well as their physical health. In this study, therefore, relationships between fast food intake frequency and food behavior, sociability, and personality, such as anger expression, were surveyed from 1,295 adolescents (666 in Seoul, 316 in Changwon, and 313 in rural communities), and then analyzed using SPSS program. The results are shown as follows. The fast food preference score and the fast food intake frequency score showed no differences between male students (22.9/30, 14.4/30 respectively) and female students (23.0/30, 14.0/30 respectively). But, the fast food preference score correlated positively with the intake frequency score (r=0.304) significantly (p<0.001). The more frequently eating of fast food group showed significantly lower scores (r=-0.233, p<0.001) in food behaviors. The frequency of fast food intake had no relationships with sociability, but it had a significantly effect on anger expression (r=0.213, p<0.001) and control (r=-0.l47, p<0.001). From these results, we could see the necessity of various nutrition education programs to build proper eating-out habits and also more studies are needed to find the relationships between fast food intake and growth and personality.