Rapidly progressive glomerulonephritis(RPGN) is the most severe form of glomerulonephritis. Recently, a variety of highly specific therapeutic methods has been considered due to advances in our understandings of molecular and cellular mechanisms of glomerular crescentic formation. Although the prognosis of the patients with RPGN has improved these days, treatment related opportunistic infection and relapse are still matters of concern. Especially, in Japan, the prevalence of older patients with MPO-ANCA related RPGN is extremely high compared to other countries. To improve the prognosis of Japanese patients with RPGN, a prospective randomized trial with specific protocol for older patients with MPO-ANCA related RPGN should be conducted.