The purpose of this study was to assess the nutrition knowledge and the factors determining this knowledge in Iranian college basketball and football athletes. By highlighting gaps in nutrition knowledge of these athletes, sport nutrition professionals may begin to address these gaps by educating athletes with a view toward minimizing injury and enhancing sport performance. Sixty-six basketball and 141 football players (response rate 78.4%) from 4 medical and 8 nonmedical universities in Tehran agreed to participate in this cross-sectional study. A 2-part questionnaire was used; the first part comprised questions identifying demographic information, and the second part comprised a previously well-validated questionnaire on sport nutrition knowledge. The overall knowledge score was 33.2% (+/- 12.3%). Men scored 28.2% (+/- 12.7%), and women, 38.7% (+/- 14.2%). In both genders, the highest score was obtained for the nutrients subcategory, and the supplements subcategory was the most poorly answered. When compared with their peers, a significantly higher score was obtained by women (p < .001), athletes at medical universities (p < .001), and those obtaining nutrition information from reputable sources (p = .03). The coach was cited by 89.4% of athletes as their main source of nutrition information. This study showed that the sport nutrition knowledge of these athletes is inadequate. Considering that this substandard level of knowledge may contribute to poor dietary behaviors, these athletes would benefit from nutrition-related training and education.