Basal levels of serum 25-hydroxy vitamin D (25-OHD) were estimated in ten normal children and twenty-seven children with protein-energy malnutrition. 2. Five normal children and fourteen malnourished children were administered a single massive dose of 15 mg vitamin D orally and the remaining children received oral supplements of 50 micrograms vitamin D daily for 20 d. Blood samples were obtained after 10 and 20 d of dosing and serum 25-OHD levels were repeated. 3. The basal serum 25-OHD levels were significantly lower (P less than 0.05) in malnourished children than in normal children. 4. Administration of a single massive dose of vitamin D as well as daily supplementation of small doses resulted in significant increases in serum 25-OHD levels within 10 d. However, the increase with a massive dose was of a higher magnitude. There was no significant difference between the normal and malnourished children. 5. The binding capacity of serum to 25-OHD was similar in both the groups. 6. These results suggest that vitamin D metabolism is not altered in protein-energy malnutrition.