Production of NO, sVCAM-1, Et-1, FV, PAI- 1 was measured in blood sera of children with different forms of chronic glomerulonephritis. Endothelial dysfunction (ED) occurred in the active phase of the disease and persisted during remission regardless of the clinical form of glomerulonephritis. Severity of ED and involvement of its markers depended on morphological type of the disease. Production of endothelin-1 was highest in patients with sclerotic glomerulonephritis and accompanying arterial hypertension. ED caused activation of hemostasis with the prevalence of prothrombotic condition. ED contributed to the progress of glomerulonephritis acting via sclerotization and cell proliferation. Selected markers ED are shown to be of prognostic value in children with chronic glomerulonephritis.