Henoch-Schönlein purpura (HSP) is the most common form of systemic small-vessel vasculitis in children. Previous studies suggested endothelial nitric oxide synthase (eNOS) plays an important role in the pathogenesis and clinical manifestations of HSP. This study aimed to investigate the potential association between 10 single-nucleotide polymorphisms (SNPs) within the eNOS gene and HSP risk and nephritis development in a Chinese Han population.