The state of Utah has had 25% lower mortality than the U.S. as a whole from cancer of the uterine cervix over the past 20 years. Members of the Church of Jesus Christ of Latter-day Saints (Mormons) have rates of cervical cancer 50 per cent below those of the non-Mormons in Utah, and contribute the bulk of their reduction in cancer mortality. A case control study is underway to test the known risk factors: early age at first intercourse, exposure to multiple sexual partners, exposure to venereal disease, etc., in 350 women with cervical cancer and 350 women selected from the general population. A survey instrument has been developed, and approximately 40 per cent of the cases interviewed.