A fifty seven-year-old female without significant past medical history presented with persistent 2+ proteinuria with normal serum creatinine levels. Subsequent clinical evaluation detected a monoclonal peak corresponding to kappa light chain on urine protein electrophoresis with 24-hr urine total protein of 449 mg (monoclonal protein, 53%). Serum free kappa light chain level was increased at 690 mg/L with a kappa/lambda ratio of 38. Bone marrow biopsy revealed 30% plasma cells with kappa light chain restriction. Myeloma- defining events, such as hypercalcemia, anemia, and bone lesion, were not present. A kidney biopsy was performed.