There are a considerable number of reports suggesting a common pathogenesis of IgA nephritis(IgANn) Henoch-$Sch{ddot{o}}nlein$ Purpura(HSP). In previous reports, a patient develops IgAN after kidney transplantation for HSP nephritis, one of Identical twin boys, developed IgAN and the other HSP, and a boy with IgAN later developed HSP. We report two cases, one with IgAN who later developed HSP and the other with HSP who later developed IgAN, suggesting that IgAN and HSP have a common pathogenesis. (J. Korean Soc Pediatr Nephrol 5 : 59- 63, 2001)