The hydroxyproline index was used to evaluate nutritional status of four- to five year-old black children in two Mississippi counties. Positive partial regression coefficinets were highly significant for weight in both counties and significant for height in one. These data seem to confirm results of other workers that changes in the index may reflect change in body weight rather than in hydroxyproline; creatinine ratio. Eighty per cent of the children had high serum gamma globulin levels suggesting infection, which has been shown to cause a high degree of variability in hydroxyproline excretion. Results indicate that hydroxyproline index may not be a valid indicator of nutritional status for this popualtion group.