Objectives. We explored differences in adolescents' eating habits, perceptions, and dietary intakes by food security status. Methods. As part of Project EAT (Eating Among Teens), we surveyed 4746 multiethnic middle and high school students in 31 primarily urban schools in the Minneapolis-St. Paul, Minnesota, area during the 1998-1999 academic year. Participants completed in-class surveys. We used multiple regression analysis to characterize associations between behaviors, perceptions, nutritional intake, and food security status. Results. Compared with food-secure youths, food-insecure youths were more likely to perceive that eating healthfully was inconvenient and that healthy food did not taste good. Additionally, food-insecure youths reported eating more fast food but fewer family meals and breakfasts per week than did youths who were food secure. Food-insecure and food-secure youths perceived similar benefits from eating healthfully (P=.75). Compared with those who were food secure, food-insecure youths had higher fat intakes (P<.01). Food-insecure youths were more likely to have a body mass index above the 95th percentile. Conclusions. The eating patterns of food-insecure adolescents differ in important ways from the eating patterns of those who are food secure. Policies and interventions focusing on improving the foods that these youths eat deserve further examination.