Two cases of Werner's syndrome are reported. The first case is that of a man with grey hair since his 20s, and alopecia since aged about 50 years. At the age of 53 years, Werner's syndrome was diagnosed, along with a malignant soft tissue tumour of the hand. The patient underwent ray amputation for the tumour. The subsequent histopathological diagnosis was synovial cell sarcoma, and the patient died of lung metastasis at 15 weeks postsurgery. The second case is that of a woman diagnosed with diabetes mellitus when aged 34 years. At 39 years, a bilateral cataract was diagnosed and at 40 years, diabetic gangrene of the left calcaneal region and calcaneal osteomyelitis necessitated left below-knee amputation. The incidence of Werner's syndrome in Japan is extremely high (1000 of the around 1300 cases reported worldwide) compared to other countries. Most patients develop malignant tumour or arteriosclerosis, the most important complications of this syndrome. The average life expectancy for patients with Werner's syndrome is 46 years. The incidence of epithelial cancer and mesenchymal sarcoma is 10 times that of the general population. The onset of symptoms of Werner's syndrome generally precedes any later symptoms of associated conditions, such as malignant tumour. Therefore, early recognition of Werner's syndrome is important to assist identification of malignant tumours at an early stage in this patient group.