A group of 18 long-stay hospital psycho-geriatric patients (aged 64-101 years) and a group of 10 healthy elderly subjects (aged 53-67 years) who were living in their own residence were studied. The group of geriatric patients were suffering from some degree of pressure sores, dementia, irritability and anorexia. Biochemical tests on vitamin adequacy with particular references to ascorbic acid, thiamine and retinal were performed in the subjects. The thiamine status was measured by determining the thiamine pyrophosphate stimulating effect of transketolase enzyme activity in whole blood. The ascorbic acid and retinal nutritures were determined by measuring their levels in plasma. From the biochemical data of the vitamins it would appear that a significant proportion of the long-stay hospital psycho-geriatric patients may be at risk of thiamine, ascorbic acid and retinol deficiencies.