A case of Werner's syndrome associated with a gastric cancer, which is the second case reported in Japan, is reported with some consideration of the literature. The case was a 47-year-old man who was admitted to our hospital with the chief complaint of bloody stool. He was diagnosed having a gastric cancer, and distal partial gastrectomy was performed. On the admittion the patient presented sclerodermalike signs, gray hair, alopecia "masked" face, a high-pitched voice, sexual underdevelopment and deformity of limbs, so he was diagnosed as Werner's syndrome. Forty-five cases of Werner's syndrome with a malignant tumor have been reported in Japan. Sarcoma and malignant melanoma were frequently included in those cases. Two cases of Werner's syndrome with gastric cancer including this case were reported in Japan. Operations for malignant tumors were performed in 19 out of 31 cases reported in Japanese literature, and 8 were alive, another 8 dead, and 3 unknown. All of dead cases died neither of operation, nor of metabolic abnomality of the connective tissues, but of cancer. Accordingly it was thought that operation for Werner's syndrome with an operable malignant tumor should be performed as well as common malignant tumors.