To evaluate the effectiveness of mass screening for uterine cancer in Japan, we compared the changes in the age-adjusted rates of potential years of life lost (PYLL) due to uterine cancer between 1969 and 1972 to 1973 through 1977 between the high coverage-rate (intensively screened) areas and the comparable control areas. The percent reduction in the average age-adjusted rate of PYLL due to uterine cancer and the years of life saved per 100,000 females were greater in the high coverage-rate areas than in the control areas. These results suggested that mass screening programs for uterine cancer contribute to saving years of life.