Micropolyarteritis are defined as necrotizing inflammatory lesion of the wall of small vessels affecting different organs. A necrotizing crescentic glomerulonephritis without immuno-deposits is observed in the kidney, frequently involved in this microscopic form of systemic vasculitis. Micropolyarteritis are regrouped with Wegener's syndrome and isolated pauci-immune necrotizing crescentic glomerulonephritis as "ANCA-related vasculitis", whose diagnosis is assessed throw renal biopsy and prognosis dependent on immuno-suppressive treatment. Sixty-one patients treated in our nephrology department for a RPGN during these ten recent years have been retrospectively studied. Among them, twenty-five patients presented clinical and morphologic aspects compatible with the diagnosis of micropolyarteritis. We present their clinical aspects and evolution under treatment.