Incidence and mortality rates of colorectal cancer (CRC) are increasing gradually in Japan; the rapid increase in elderly population led to an increase in incidence rate in 50 years or older and mortality in 80 years or older. The mortality and morbidity for elderly patients with comorbidities after surgical treatment for CRC are extremely high. Also the 5-year-survival rate in elderly patients is significantly lower than that of non-elderly patients. Although reduction of lymphadenectomy or laparoscopic procedure is applied to elderly patients, an analysis of the validity is necessary. Because of high complication rates for surgeries in elderly patients, there is an immediate need to develop Japan's own accurate risk assessment such as comprehensive geriatric assessment.