Rapidly progressive glomerulonephritis (RPGN) is a dramatic disease that carries a poor prognosis but responds to early intervention and aggressive therapy. This review provides a schema for expeditious diagnosis and therapy of various types of RPGN encompassing application of current serological and other diagnostic tools, and addresses issues related to selection of therapy, assessment of expectation of response, and prognosis. Current therapeutic modalities have improved the prognosis of this devastating disease, but emerging therapeutic options promise to improve our treatment of these diseases yet more in the future.