Introduction: The role of diet is crucial in the prevention of diseases. Physicians and health staff can play a vital role in decreasing disease. The purpose of this study was to determine the knowledge, attitude, and practice of Iranian health staff toward nutrition. Methods: In a cross-sectional study on 473 health staffs of the Iranian health staff from 30 provinces of Iran were involved in this study during 2011-2012. The sampling method in this study in each province was stratified random sampling. KAP was assessed by a self-administered questionnaire. Results: Approximately 40%-90% of participants knew the main groups of food; 44%-74% of them had information about importance of micronutrients, and the knowledge of health and nutritional needs of pregnant and lactating mother was84%-88%. Health staffs’ favorite attitude toward the major food groups and micro-nutrition were 49%-90% and 26%-86%, respectively. And for the major food groups was 28%-98% and practice about health and nutritional needs of pregnant women and mothers was 80%-92%. Conclusion: This study shows health staffs need more training on some topics of nutrition in Iran. Consequently, intervention programs and nutrition education to improve employee performance in the health center is necessary. Manuscript profile