A case of multiple myeloma combined with stomach cancer and related literatures were reviewed. A 67 year-old male patient entered the hospital with dysphagia and weight loss for 3 months. Peripheral blood examination revealed anemia with rouleaux formation. Total protein of the serum was 9.9g/$d{ell}$ with hyperglobulinemia(albumin 2.7g/$d{ell}$, globulin 7.2g/$d{ell}$, A/G ratio 0.375). On the electrophoresis and immunoelectrophoresis of the serum, the abnormal protein with the pattern of monoclonal gammopathy(IgG-K type) was shown. There were multiple variable sized osteolytic lesions on skull X-ray and abnormal hot uptakes of ribs on bone scan and result of rib biopsy was plasmacytoma. Gastrofiberscopy was performed to search for the cause of upper gastrointestinal bleeding, revealed stomach cancer, and the result of the gastric mucosal biopsy proved to be well-differentiated adenocarcinoma.