Henoch-Schonlein purpura (HSP) is one of the most common types of vasculitis disorders seen in childhood and is characterized by a rash, arthritis, abdominal pain, and renal involvement. Although HSP is an immunoglobulin A (IgA) related immune complex disease, the pathogenesis has not been fully elucidated. Cytokines have been implicated in the pathogenesis, but endothelins (ET) - vasoconstrictor hormones produced by endothelial cells - have not been studied in patients with HSP In a controlled study, we measured ET-1 levels in children with HSP during the acute and remission phases. ET-1 levels were significantly higher in the HSP patients during the acute phase compared with the control group and the HSP patients in the remission phase. There was no correlation between ET-1 levels and disease severity, acute phase reactant response, or morbidity. The role of endothelins and other cytokines in the pathogenesis of HSP needs to be further explored.