This case report describes a 54-year-old, asymptomatic man who presented with hyperkalemia on routine lab testing who was later found to have acute renal failure, unresponsive to fluid resuscitation, with minimal improvement after hemodialysis. After a comprehensive evaluation ruled out common causes of acute renal failure, the patient underwent testing with a bone survey, urine protein electrophoresis (UPEP), serum protein electrophoresis (SPEP), and immunoelectrophoresis for suspected plasma cell dyscrasia and received plasmapheresis for hyperviscosity syndrome and nephrotoxicity, which resulted in improved renal function. Lab results showed monoclonal gammopathy, elevated serum free light chains, and Bence Jones protein in the urine with a follow-up bone marrow biopsy indicating plasma cell dyscrasia. The patient received a diagnosis of multiple myeloma (MM) and was started on chemotherapy and immunosuppression. In patients presenting with acute renal failure with an evaluation ruling out prerenal and postrenal causes, multiple myeloma should be considered.