The study purpose was to investigate the factors related to fast food consumption of university students. Factors were identified using the Theory of Planned Behavior. Based on the pilot study, 18 behavioral beliefs, 7 normative beliefs and 19 control beliefs were identified. Data (n = 269) were analyzed using analysis of variance or X² tests. Subjects were categorized into non-users (27.9%), users (42%) and frequent users (≥ 2 times/week, 30.1 %). Regarding behavioral beliefs, users or frequent users responded more positively on advantages of eating fast foods including `taste` (p < 0.001), `making me feel full` (p < 0.001), `diverse menus` (p < 0.05) than non-users. Compared to users, non-users responded more positively on the item that eating fast foods leads to eat vegetables less (p < 0.05), and negatively on `making me eat more salt` (p < 0.05). Most of the referent groups, parents (p < 0.001), sisters/brothers (p < 0.01), relatives (p < 0.01), friends (p < 0.05), boy/girl friends (p < 0.05) were important sources of influence regarding subjects` fast food consumption. Users or frequent users felt less control over factors or situations that make it consume fast foods (9 out of 19 control beliefs). These factors included; availability issues (p < 0.001), `not having other foods on hand` (p < 0.01), `others eating together like fast foods`, `convenience`, `social increase in fast food use`, `easy to get fast foods anytime` (p < 0.05). In addition, users of fast foods were more likely to eat fast foods when they don`t have time, when they do not like to cook, when they feel hungry (p < 0.05). These results suggest that interventions for university students include strategies to moderate fast food use by modifying behavioral beliefs, suggesting alternative menus and behavior modification techniques, increasing perception of control, and eliciting social support. (Korean J Community Nutrition 9(1): 47~57, 2004)