In a cross-sectional study X-rays of the forefoot and the pelvis of 101 adult dialysis patients were taken. Vascular calcifications (forefoot) were observed in 20 patients. The incidence was higher in patients who had been started on dialysis several years ago. However, in a longitudinal prospective study de novo appearance of vascular calcificaitons was observed only in 1 out of 50 dialysed patients, although hyperparathyreoidism and moderate hyperphosphatemia persisted. Vascular calcifications were seen only once in 138 uremic children (56 uremic children without dialysis; 82 uremic children on maintenance hemodialysis). However at autopsy visceral calcifications of the lung were found in three (out of 11) children who did not have vascular calcificaitons on X-rays.