Serum 25-hydroxycholecalciferol (25[OH]D3) levels and other parameters of vitamin D nutriture were examined in 58 subjects aged 70 or more, living in Jerusalem. They were compared with those of 54 young adults living in the same neighbourhood. No evidence was obtained of a lower level of vitamin D nutriture in the elderly compared to younger adults. Serum 25(OH)D3 of the elderly adults was 18.4 (SEM: 1.4) ng/ml and in the younger adults, 17.8 (1.0) ng/ml. There was no seasonal variation in serum 25(OH)D3, nor could a strong association be found between reported vitamin D intake nor with exposure to sunshine. There was a negative correlation between serum alkaline phosphatase and the calcium-phosphorus product in serum. High values of alkaline phosphatase were associated with reported low exposure to sunlight and, in elderly persons, with a reported low consumption of vitamin D.