A 25-year-old woman was admitted because of proteinuria. A renal biopsy showed mesangial/endocapillary proliferative glomerulonephritis with IgG2-κ deposits. Electron microscopy showed immune complex-type deposits. She also had Coombs-positive hemolytic anemia, anticardiolipin antibodies, and antinuclear antibodies. Middle-dose steroid therapy led to improvement of proteinuria and hemolytic anemia. Six years later, she developed crescentic glomerulonephritis with IgG2-κ deposits during pregnancy. Middle-dose steroid therapy improved renal dysfunction. This is an exceptional case of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID), a recently described rare dysproteinemia-related glomerulonephritis, associated with autoimmune disease. This case also suggests that crescentic glomerulonephritis can be superimposed on PGNMID.