Despite the public’s perception, widespread malnutrition following disasters is not common. The disasters that are most likely to result in significant malnutrition are those that occur in developing nations and that destroy or restrict access to major food supplies. Both protein-energy malnutrition (PEM) and micronutrient malnutrition can occur. PEM occurs when the diet lacks sufficient calories and protein to meet daily needs. Common types of micronutrient malnutrition seen in disasters are deficiencies of Vitamin A, Vitamin C, Iron, and Niacin. Both types of malnutrition often take several weeks or months to develop. Certain diseases such as diarrhea and measles can promote malnutrition due to impaired absorption of nutrients. Particularly vulnerable populations include families headed by women, unattended children, the elderly, and pregnant or lactating women. Measures to prevent malnutrition following a disaster include assuring that emergency food supplies are nutritionally complete, that food is distributed equitably among the affected population, that safe drinking water is available, that adequate sanitation is maintained, and that diseases which promote malnutrition are controlled.