Appropriate nutrition is a prerequisite for effective improvement of athletic performance. Nutritional supplements have been widely used in various sporting fields to boost the recommended daily allowance. The purpose of this study was to describe different dietary habits and its relation to exercise in group of high performance Egyptian athletes and assess their knowledge, attitude and practice toward the use of nutritional supplement. Methods: Athletes (n=121) from four different sports (basketball, football, swimming and modern pentathlons) completed an anonymous structured assisted questionnaire detailing their anthropometric measures, dietary habits in relation to sport and their attitude, practice and source of knowledge regarding supplement use. They completed a three day dietary record as well in order to be analyzed. Results: Average daily energy intake was 2897.3 ± 935.7 Kcal/day with males consuming more calories than females (3116.7± 1016 and 2095.5 ± 644.7 Kcal/day, respectively; P < 0.05). Carbohydrate, protein, and fat accounted for 45.8%, 30.3% and 23.9% of daily calorie intake, respectively. Average daily carbohydrate and protein intake was 4.5 ± 2.1 and 1.6 ± 0.5 g/kg body weight, respectively. Majority of athletes did not consume adequate energy or carbohydrates or proteins. Most of their micronutrient intakes didn’t reach current RDI values. The percentage of athletes who agreed on taking supplements were 53.7% and 47.9% actually used them. The most popular supplements used were multivitamins (72.4%). Athletes sought advice on supplement use mainly from doctors (60.0%). Increasing performance was their major motive for use (77.6%) while saying its harmful was their major reason for refusing (42.9%). Conclusion: The majority of high-performance Egyptian athletes did not consume adequate energy, carbohydrates or proteins. Their intake of most micronutrients did not reach current recommended daily intakes, indicating that athletes made low-quality food choices. The main reason for consumption of supplements was to increase performance. The number one source of information sought was physicians’ recommendation. The most popular supplements used were multivitamins.