Thirty-two protein-calorie malnourished (PCM) children were studied on admission to hospital and throughout recovery. Absorption studies included nitrogen, fat, purified¹³¹I-labeled triolein and oleic acid, vitamin A palmitate, glucose,d-xylose, and vitamin B₁₂. Protein depletion was measured by the creatinine/height index (CHI). Severe malabsorption of all substances was present in all severely malnourished children (CHI<0.55). As children became less protein-depleted with nutritional recovery, malabsorption decreased, in the following sequences: absorption of nitrogen,d-xylose, and vitamin A palmitate recovered soon after initiation of therapeutic diets; absorption of fat, purified¹³¹I-triolein and-oleic acid, and vitamin B₁₂ recovered slowly and in a highly correlated fashion. Results with both purified¹³¹I substrates were identical throughout. The findings of this investigation are compatible with the concept that malabsorption in protein-calorie malnourished children affects mucosal function throughout the gut as a consequence of protein depletion per se.