The objectives of this study were to evaluate high school coaches' knowledge in sports nutrition and the nutritional practices they recommend to their athletes. Forty-seven high school coaches in "leanness" and "non-leanness" sports from the greater region of Quebec (women = 44.7%) completed a questionnaire on nutritional knowledge and practices. "Leanness sports" were defined as sports where leanness or/and low bodyweight were considered important (e.g., cheerleading, swimming and gymnastics), and "non-leanness sports" were defined as sports where these factors are less important (e.g., football). Participants obtained a total mean score of 68.4% for the nutrition knowledge part of the questionnaire. More specifically, less than 30% of the coaches could answer correctly some general nutrition questions regarding carbohydrates and lipids. No significant difference in nutrition knowledge was observed between coaches from "leanness" and "non-leanness" sports or between men and women. Respondents with a university education scored higher than the others (73.3% vs. 63.3%, p < .05). Coaches who participated in coaching certification also obtained better results than those without a coaching certification. The most popular source of information about nutrition used by coaches was the Internet at 55%. The two most popular nutrition practices that coaches recommended to improve athlete performance were hydration and consumption of protein-rich foods. Recommendation for nutritional supplements use was extremely rare and was suggested only by football coaches, a nonleanness sport. Findings from this study indicate that coaches need sports nutrition education and specific training.