Henoch-Schönlein purpura (HSP) is a systemic disorder characterized by leukocytoclastic vasculitis involving the capillaries and the deposition of IgA immune complexes. Renal involvement is the principal cause of morbidity and mortality in children with HSP. Thus, it is important to clarify the onset mechanism of Henoch-Schönlein purpura nephritis (HSPN) and to identify the most appropriate treatment. We herein review the pathogenesis and treatment of HSPN. As to the pathogenesis, several studies suggest that galactose-deficient IgA1 is recognized by anti-glycan antibodies, leading to the formation of circulating immune complexes and their mesangial deposition, thereby inducing renal injury. Aggressive therapies for the treatment of severe HSPN, including multiple drug combination therapy and plasmapheresis, have been shown to be effective in ameliorating proteinuria and histological severity. Nevertheless, detailed investigations of the pathogenesis of HSPN and double-blind randomized control studies on children with HSPN are still necessary.