Serum zinc levels measured by atomic absorption spectrophotometry were found to be low (less than 10.5 mumols/l) in 38% of acute geriatric admissions, 69% of long stay geriatric patients and 19% of a control group of elderly hospital patients with a normal serum albumin. There was a significant positive correlation between serum zinc and serum albumin in all groups. In acutely ill geriatric patients only, there was a weak but statistically significant positive correlation between serum zinc and alpha-2-macroglobulin (A2M) (r = 0.20), P less than 0.05). Serum transferrin was low in 46% of acute geriatric patients and 22% of long stay geriatric patients but there was no correlation between serum zinc and serum transferrin levels in any patient group. There were significant differences in serum zinc, A2M and transferrin levels between the acute and long stay geriatric patients. The differences in serum zinc levels between these patients groups could not be explained by changes in serum A2M, transferrin or albumin. Changes mediated by an acute phase response may have influenced results in the acute geriatric group of patients.