A case of multiple myeloma associated with adenocarcinoma of the stomach and related literatures were reviewed. The patient was a 45-year-old man presenting with multiple osteolytic punched out defects in skull X-ray films. Laboratory findings revealed anemia, Bence-Jones proteinuria and plasmacytosis. The findings of bone marrow aspiration revealed plasma cell myeloma. Immunoelectrophoresis appeared IgG-kappa type. Histopathologically, adenocarcinoma of stomach mucosa obtained by gastrofiberscopy was confirmed.