Incidence rates of cancer of the corpus uteri have been estimated from a one per cent sample of hospital discharges in the United States for the years 1970–1975. Among postmenopausal women, rates rose sharply In 1970–1975, while for younger women there was little net change. There were substantial regional variations in Incidence, which were largest between the ages of 65 and 69 years. All rates have been corrected for the numbers of women In each region and age group with uteri intact.