One hundred and fifty four patients with hemolytic uremic syndrome (HUS) were admitted from year 1968 throughout 1989 to a public children's hospital (n = 139) and to a private general clinic (n = 15) at Metropolitan Santiago, Chile. Their mean age at admission was 16 months, 64% of them were 6 to 18 month old. One third of patients were admitted at spring season. The prodromal phase lasted between 1 and 19 days. In 92% of cases there was antecedent diarrhea and 31% showed neurological involvement. Anuria was present in 44 patients (21%) lasting an average of 7 days; sixty one affected children (40%) became hypertensive. Sixty patients (39%) underwent peritoneal dialysis, remaining cases were given maintenance treatment for acute renal failure (ARF). No specific treatment was used except heparin in 5 children along the first years of these series. Ten patients (6%) died during the acute phase of their disease, but death occurred in only 2 of the 76 most recent cases, probably because of more accurate diagnosis and greater experience of the professional team in the management of ARF, even though very heterogeneous clinical presentations were observed along the whole observation period. Three patients developed chronic renal failure.