Summary Thirty-four malnourished subjects between the ages of 61 and 97 years were given appropriate food supplement(s) for a period of 6 consecutive months. They were followed for a subsequent 6 months during which time there was no nutritional intervention. Nutritional assessment and immunological evaluation were performed at 0, 6, and 12 months. Nutritional assessment included anthropometry, biochemistry, and clinical examination. Immunological evaluation included serum complement C3 concentration, delayed cutaneous hypersensitivity skin test, and the enumeration of total lymphocytes, rosetting T-cells, CD4÷ cells, and CD8 + cells. Immune function improved by the end of the supplementation period. Six months of nutritional supplementation significantly increased the percentage of lymphocytes represented by mature T-cells.