Background: It is the 21st century and junk food has gone global. Far worse, junk food is now available everywhere all over the world. Objective: to measure the effect of a nutrition education program on medical students' knowledge and behavior and to evaluate their knowledge and behavior regarding junk food. Method: A total of 184 medical students from Beni- Suef University were enrolled in this non controlled intervention study. A self-administered questionnaire was used to assess the students' knowledge and behavior about junk food, before and after being subjected to a nutrition educational program. Results: Of the 184 medical students, (36.4%) were males while (63.6%) were females. The mean age of students was (20.45±1.24) years (range 18–23 years).The nutrition awareness program resulted in statistically significant improvement (p<0.001) in students' knowledge and behavior. 87.5% and 55.4 % of medical students were aware of the definition and the composition of the junk food respectively. Time constraints and the availability of junk food were the main cause to choose junk food among students with suboptimal behavior (29.5% and 23.3% respectively). Conclusion: the interventional awareness program showed a positive influence on improving the knowledge and behavior of medical students of Beni- Suef University regards junk food.