The late outcome in 89 children with the hemolytic-uremic syndrome (HUS) oberved from 1971 to 1988 was analyzed up to 17 years after onset in relationship to various clinical and pathologic features at the onset of the disease. In the first 3 months after onset (acute phase) 69% of all children needed dialysis therapy. Fifteen children died, 9 during the acute phase and 6 subsequently. All surviving patients except 7 were reexamined and divided into five prognostic categories: recovery, residual renal symptoms with normal kidney function, moderate renal insufficiency, preterminal chronic renal failure (CRF) and end-stage renal disease (ESRD). The rate of recovery calculated by the life table method increased from 35% after 10 years in 1971-1979 to 68% in 1980-1988 (p < 0.001); it was lower in infants than in older children (44 vs. 63%; nonsignificant). Children with an atypical HUS experienced more often preterminal CRF, ESRD or death than those with a typical (postenteropathic) form (33 vs. 17%; p < 0.05). If oliguria lasted < 7 days, 74% of patients recovered after 10 years versus 13% in the case of oliguria > 14 days or anuria > 7 days (p < 0.0005). The rate of recovery was also significantly smaller with the duration of dialysis treatment > 7 days, central nervous system involvement and requirement for antihypertensive therapy. In the entire series 7 patients developed preterminal CRF and 5 ESRD. Of 27 cases serially followed for 5-10 years after onset, a stable course was noted in 16, a subsequent improvement in 8 and deterioration in 3 leading to ESRD in 2. In conclusion, the study demonstrates a high incidence of chronic kidney disease in patients who have suffered from HUS. Late deterioration of renal function after apparent recovery underlines the need for continuing follow-up examinations for at least 10 years.