Abstract:Today it is proved that the lack of adequate nutritional knowledge leads to problems such as obesity, overweight and increased cardiovascular diseases. However, many obstacles such as poor financial support, lack of time and poor nutritional knowledge can influence achievement of optimal nutrition which is proportional to the level of the athlete's physical activity. The purpose of this study was to determine the level of nutritional knowledge and dietary behavior of athletes in Khorramabad in 2013. Professional athletes of Khorramabad, Iran, with more than one year of regular exercise and at least one course participating in national championships competitions were studied in this cross-sectional, descriptive-analytic study. The samples included 247 athletes aged 17-29 years. Their nutritional knowledge and behavior were measured by the nutritional knowledge and behavior inventory. Results: The results showed a significant difference in nutritional knowledge of athletes by gender and educational level; female athletes have higher nutritional knowledge than male athletes. A gender-dependent difference was found in nutritional behavior; despite their higher nutritional knowledge, female athletes have weaker nutritional behavior than male athletes. However, no significant correlation was found between BMI and nutritional knowledge and behavior of the athletes. Moreover, findings showed that nutritional knowledge and behavior could be significantly different in various sports.