Introduction: Shift work means working at times out of normal daylight hours (8:00 am to 2:00 pm) or work during the weekends. Also it refers to a work schedule that involves irregular or unusual hours, such as night work and rotating shift work, in contrast to normal daytime work. Shift workers prefer to eat fast foods and tend to have fewer meals over 24 hours. Security guards experience shifts that negatively affect their dietary behavior and nutritional status. Aim of work: To assess the effect of shift work on dietary habits and nutrients intake among the security guards at Mansoura University. Materials and methods: A cross sectional study of all (166) security guards at Mansoura University who were exposed to an interviewer–administrated questionnaire for socio-demographic data and occupational history, anthropometric measurement, evaluation of dietary habits and dietary survey. Results: Mean±SD of Body Mass Index (BMI) (34.6±8.8) and waist circumference (105.1±15.9 cm) were statistically significantly higher among night shift guards than those with other shifts. Number of meals was statistically significantly fewer (2 meals/day) but snacks number was significantly higher (> 3 snacks/day) among night shift guards. Night shift guards had the highest daily carbohydrate and fat intake and lowest daily protein intake with a statistically significant difference with other shifts. They also had the lowest daily intake of iron, calcium and vitamin. Conclusion: Security guards with night shift experienced few meals intake with more snacks during their shift with reduced intake of protein, iron, calcium and vitamin A and with increased carbohydrate and fat intake.