We describe a spectrum of clinical and morphologic features which may occur in idiopathic crescentic glomerulonephritis. Of note are patients who pursue a more indolent course to renal failure in contrast to typical rapidly progressive glomerulonephritis (RPGN). Patients following this protracted course have an insidious presentation with hematuria and renal insufficiency, and at the time of renal biopsy (usually after many months of clinical illness) show less extensive involvement with crescents, which are often in both cellular and fibrous stages. This form of crescentic glomerulonephritis is further distinguished from RPGN by frequent hypertension and the nephrotic syndrome, the absence of oligo-anuria and progression to renal failure over many months or even years.