Late symptoms of infantile cystinosis were evaluated in 19 patients aged 15-26 years who had a high graft survival following kidney transplantation. The end-stage cystinotic kidney was responsible for renal hypertension in 5 patients following grafts. Photophobia did not increase in relation to age, but 3 patients became blind and 1 lost the sight in one eye at 25 years of age. Two patients developed clinical symptoms of hypothyroidism, and 15 other patients had a compensated hypothyroidism. Four patients developed permanent insulin-dependent diabetes and 2 developed transient insulin-dependent diabetes after transplantation. The oral glucose tolerance test was abnormal in 11 of 14 patients on low-dose prednisone. Liver enlargement was noted in 10 cases, but only 3 patients developed clinical symptoms of portal hypertension. Symptoms of hypersplenism were observed in 6 cases leading to splenectomy. Repeat gross epistaxis was observed in 7 of the patients when on dialysis and persisted after transplantation in 1 patient, who died from nasal bleeding. A particular encephalopathy developed in 2 patients at the ages of 17 and 24, characterized by speech difficulties, pyramidal symptoms and cranial nerve deficit; one died at the age of 21. The mean adult height of these patients was 136.5 cm in males and 124 cm in females, and their psychosocial adjustment was related to the extra-renal complications of cystinosis rather than to the renal status.