Rapidly progressive glomerulonephritis, the term coined for a subtype of nephritic syndrome, is characterized by a state of acute loss of renal function, along with those components of renal damage on urinalysis, over a relatively short period (a few weeks or months). It is the aftermath of an acute, severe glomerular injury. RPGN, famously known as Crescentic glomerulonephritis (cGN) is not a single disease entity but a pattern that can occur in a variety of glomerular diseases caused by different pathologic lesions leading to the development of necrosis in the glomerular capillaries seen in both, systemic and kidney-restricted diseases. While still little is known about the exact etiologic cause behind the primary injury to the capillary wall leading to the development of the condition, many mechanisms are put forth to describe the pathogenesis leading to the progression. Immunopathologic studies have demonstrated that rapidly progressive glomerulonephritis can result from glomerular antibody deposition, can be immune complex-mediated, or from some as yet undefined mechanism that doesn’t involve glomerular antibody deposition. The condition is often severe with poor prognosis as it develops so rapidly and with extensive glomerular involvement, the damage is almost irreversible. Many elements can be associated with the occurrence and progression of the disease but it often involves a disruptive immune response one way or the other. RPGN’s morphological hallmark, the extensive extra-capillary cellular proliferation into the bowman’s space, commonly known as crescent formation which is often observed by electron microscopic view of the tissue biopsy, is considered one of the great diagnostic approaches for the detection of the disease. Also, the severity of the disease is related to the nature and type of immunologic process causing the disease and (in part) to the degree of crescent formation, that can only be observed by histopathological studies. This activity attempts to explain the etiology and pathogenesis involved in the development leading to the rapid progression of the disease.