The most frequent causes of glomerular diseases whose main clinical syndrome are nephrotic syndrome and acute renal failure may have several causes: acute tubular necrosis, thrombosis of renal veins, acute tubulointerstitial nephritis. Infrequently, the association between primary glomerular disease (membranous nephropathy and others) and crescentic glomerulonephritis can cause this clinical picture. We describe a young woman without systemic disease with nephrotic syndrome and acute renal failure secondary to membranous nephropathy and superimposed crescentic glomerulonephritis. She received steroids and cyclophosphamide with stabilization of renal function after two months of follow-up.