The aim of this study was to evaluate the long-term outcome of hemolytic-uremic syndrome in children and the dependence of outcome on severity of the acute phase of the illness. We analyzed data of 20 children who were hospitalized and treated at the Clinic of Children's Diseases, Kaunas University of Medicine Hospital, during 1995-2006. Data were obtained from case histories and outpatient case records with the help of prepared questionnaire. The course of acute disease and health status were evaluated at discharge from hospital and at 6-month, 1-year, and 3-year follow-ups. There were 8 boys and 12 girls in the study group; their age ranged from 3 months to 12 years. According to the clinical course of the acute phase of the illness, children were divided into two groups. Group A (severe course) consisted of 15 patients with blood leucocytosis (more than 20x10(9)/L) and signs of CNS involvement, who required renal replacement therapy. Group B (mild course) consisted of five children who did not have such symptoms. Twelve (60%) children underwent dialysis during acute illness; two patients died (10%). One (20%) patient in Group B had proteinuria, four (80%) had renal insufficiency, and three (60%) had arterial hypertension at discharge from hospital. Subsequently these changes disappeared, and 3 years later arterial hypertension was detected in 1 (25%) patient in Group B. Eight (61.5%) patients from Group A had renal insufficiency, nine (69.2%) had proteinuria, and two (15.4 %) had arterial hypertension at discharge from hospital. Three years later from the onset of the disease, two (20%) patients had arterial hypertension, proteinuria was detected in two (20%) patients, and renal insufficiency remained in six (60%) children. Our data revealed that the outcomes of the disease are strongly influenced by the severity of the acute phase of the illness.