Contaminated water and food are major causes of malnutrition and mortality in the developing world, particularly among children. Infants are most vulnerable to diarrheal illnesses when introduced to fluids and foods as they are weaned from breastfeeding to a mixed diet. There is scant literature about the role of nutrition professionals in addressing this problem. Considerable progress has been made in identifying strategies to prevent diarrhea in children. Strategies include implementing low-technology methods of sanitizing water, emphasizing the benefits of breastfeeding, protecting prepared foods from unclean environments, and educating and motivating food preparers. Resolution of water and food safety problems requires a collaborative interdisciplinary approach among health professionals and involvement of community leaders. Dietetic professionals have the training to empower individuals and communities with skills to create a safe water and food environment.