Diabetic nephropathy (DN) is a common complication and the leading cause of end-stage renal disease (ESRD) in diabetic patients. The occurrence of non-diabetic renal disease (NDRD) in diabetic patients has been increasingly recognized in recent years. Generally, renal injuries in DN are deemed difficult to reverse, whereas some NDRDs are often treatable and even remittable. Thus, the diagnosis of NDRD in patients with diabetes mellitus (DM) via a kidney biopsy would be significant for its prognosis and therapeutic strategy. According to recent studies, the most common NDRD is IgA nephropathy in type 2 diabetic patients, and some cases of minimal change disease and membranous glomerulonephritis have been reported in Korea. However, membranoproliferative glomerulonephritis (MPGN) is an uncommon condition in diabetic patients. To our knowledge, there has been no case yet of MPGN, except in a child with type 1 DM. We present an unusual case of a 27-year-old woman who had type 2 DM with MPGN, as confirmed via a kidney biopsy.