Acute kidney injury presenting without obvious cause is a diagnostic dilemma. One condition to be considered is monoclonal gammopathy. A case of light chain deposition disease was detected as a cause, involving kidney and extra renal site. It is a part of monoclonal immunoglobulin deposition disease, and may or may not be related to multiple myeloma. Delayed diagnosis can lead to end stage kidney disease, requiring long term dialysis, with its vascular access problems, preventing the treatment by autologous stem cell transplant. The case is presented with review of literature.