Idiopathic membranous nephropathy is one of the most common causes of nephrotic syndromes in adults but rare in childhood. The occurrence of crescentic glomerulonephritis and membranous nephropathy in a patient is rare. This report describes a patient who initially was diagnosed as a membranous glomerulonephropathy at age 12 years and subsequently developed a crescentic, rapidly progressive glomerulonephritis at age 19 years. The patient responded to methylprednisolone pulse therapy and he maintained with partial remission and normal renal function with residual proteinuria.