Among dematologic clues to systemic diseases, conditions of the oral mucosa have not often been discussed in multiple myeloma. A case is reported below which suggests that the diagnosis of multiple myeloma should be considered when puzzling mucosal findings are attended by certain constitutional signs and symptoms. As a generality, the clinical signs and symptoms of multiple myeloma depend upon where and how much plasmocytic infiltration is present in the organs of the body, and upon many subtle chemical changes that are related causally or sequentially to those infiltrations. Thus, it is common to find upon physical examination in well-developed cases, bone pain, neuropathy and weakness, and, upon laboratory investigation, anemia, excessive rouleaux formation in smears of peripheral blood, immaturity of myelogenous leukopoesis in marrow smears, Bence Jones proteinuria and elevated, abnormal serum proteins, increased serum calcium, and radiologic evidence of pathologic fractures and bony defects. The skin, of course,