We report a 72-year-old female case of IgG-kappa type multiple myeloma (MM) simultaneously complicated with Sjögren syndrome (SS). She also presented marked hyperamylasemia of salivary-type isozyme. Although she had received sequential chemotherapy completed with high-dose therapy with autologous hematopoietic stem cell transplantation, she died of relapse fifteen months after the initial diagnosis. Various autoantibodies indicated that her sicca symptoms were due to true SS and not caused by MM cell infiltration to exocrine glands. MM cells appeared to produce amylase that fluctuated correspondingly to the disease status of MM. To our knowledge, this is the first English report of simultaneous complication of SS and MM referring to hyperamylasemia. Accumulation of this rare clinical manifestation is important to elucidate the pathogenesis of MM under condition of immunological disorder caused by SS.