Mass screenings for uterine cancer have been done on 200,000 women in Shimane Prefecture, Japan, from 1972-1981. Up to 1978, a cotton-tipped applicator was used for sample procurement and since that time a wooden spatula type instrument has been used. A central, cytological diagnostic system has been used since 1979. The cytology activity index (CAI) was about 90 each year. The rate of second examination performed is about 60% for women requiring an accurate examination. Cancer detection rates increased from 0.05% to 0.12%, the false negative rate decreased, cytological and histological findings were in close parallel and the mortality rates have decreased. These positive results are attributed to the use of the wooden spatula and central diagnostic systems. By the mass screening for uterine cancer during these 10 years, 81 women were detected as having carcinoma in situ and 107 women as having invasive carcinoma in the histological findings. The number of first screenings has decreased gradually, but the number examined 6 times or more has increased. These results include that same women have tended to undergo the mass screening examination. In women over 50 y.o., particularly those 60 or over, the number screened was low, yet the incidence of invasive cancer exceeded that in other groups.