THE DIFFERENTIAL DIAGNOSIS OF FEVER of unknown origin includes infectious diseases, malignancies and connective tissue diseases. Multiple myeloma is not usually included in the differential diagnosis, nor is it considered a frequent cause of cholestasis in the absence of amyloidosis. We report a case of multiple myeloma in a patient presenting with a long-standing fever and cholestasis. The patient underwent a long and unfruitful series of diagnostic procedures, including liver biopsy. The clue to the diagnosis, established with a marrow biopsy, was the presence of a paraprotein in the serum.