We report the case of an 84-year-old female presented to us with acute onset altered sensorium. On investigation, neurological and infectious causes were ruled out. On further evaluation, her serum calcium was found elevated (15.07 gm/dl). The diagnosis of hypercalcemic encephalopathy was made with the possibility of multiple myeloma due to raised total protein and globulin levels. Serum electrophoresis, immunofixation, and bone marrow examination confirmed the diagnosis of multiple myeloma. The patient was treated with bortezomib, dexamethasone, and lenalidomide. After 1 week, she improved with normalization of serum calcium. Herein, we highlight hypercalcemia as an important cause of encephalopathy. As our report suggests, metabolic encephalopathy can be the first presentation in multiple myeloma.