The prevalences of acute and chronic protein-energy malnutrition (PEM) and deficiencies in stores of fat and somatic protein have not been previously examined in pediatric intensive care unit. One hundred eight nutritional assessments were performed using anthropometric techniques on infants and children in a multidisciplinary intensive care unit. Overall, the prevalence of acute PEM was 19% and chronic PEM was 18%. The prevalence of fat store depletion was 14% and somatic protein store depletion was 21%. In general, children less than 2 years had poorer nutritional status compared to children greater than 2 years. There was not a statistically significant difference between medical and surgical patients. It is concluded that PEM and deficiencies in the macronutrient stores of fat and somatic protein are common in critically ill infants and children.