Observations on 100 children with manifestations of severe protein malnutrition show that a fatal outcome is more likely in the presence of one or more of the following factors: (1) advanced emaciation, in this instance a body weight 50 per cent or more below average; (2) acute nutritional dermatosis; (3) clinically detectable dehydration, which in the patients in this series was often associated with markedly lowered serum sodium and potassium levels; (4) marked enlargement of the liver; and (5) hypothermia.