A combined dietary, biochemical and clinical study was carried out on 196 aged subjects residing at home and institutions (hospital, residential accommodation and sheltered dwelling) to evaluate the nutritional status of riboflavin and to assess the effect of regular vitamin supplementation. The dietary intake of vitamin B2 was below two-thirds of the recommended in 33.3 per cent males and 17l9 per cent females. Biochemical deficiency of riboflavin was noted in 7.1 per cent subjects by erythrocyte glutathione reductase (EGR) activity coefficient (AC) test. An association between activity coefficient and low intake was found when the coefficient was greater than or equal to 1.30. There was no significant correlation between activity coefficient and dietary vitamin B2/day or vitamin B2/100 g protein. Regular oral administration of multivitamin (containing 2.5 mg vitamin B2) prevented biochemical deficiency of the vitamin. Clinical signs of riboflavin deficiency were not seen except in one female subject of sheltered dwelling.