This study was undertaken because circulatory distrubances had been advanced as a possible cause of death during initial renourishing of protein-calorie deprived children. Body weight, plasma albumin concentration, intravascular volumes (radiochromium), cardiac index (dye dilution technique), intravascular pressures (flow-guided catheterization), and related hemodynamic parameters were determined at rest in 43 infection-free African children with a form of protein-calorie malnutrition known as marasmic kwashiokor, and were compared with values observed in 24 convalescent children. The malnourished children showed a prolonged circulation time with a tendency to bradycardia and hypotension; cardiac index, stroke index, and heart work were significantly reduced, as were the intravascular volumes. Hemodynamic data correlated with either body weight or plasma albumin and cardiac index bore a direct relation to red cell volume. In the most severely malnourished subjects, ventricle filling pressures were low and vascular resistances were high. It is inferred that most patients were in an adaptive hypocirculatory state comparable to hypothroidism, while the most severely malnourished children showed frank peripheral circulatory failure comparable to hypovolemic shock. Circulatory failure on admission was associated with high death rate during treatment but the relation between cause and effect could not be clearly demonstrated.