SUMMARY Utah mortality rates for cerebrorascular disease (ICD numbers 430-438) are 13% below U.S. rates. About 70% of Utahns are members of the Church of Jesus Christ of Latter-day Saints, commonly called Mormons or LDS, which proscribes use of tobacco and alcohol. Other studies on this group hare found significantly lower occurrence of many cancers and iscbemic heart disease. We tested the hypothesis that Utah's lower cerebrorascular disease (CBVD) mortality was contributed by the LDS population. We classified by religion all CBVD deaths (2,521) (except subarachnoid hemorrhage and cerebral embolism) occurring in the state in 1968-1971. No significant difference was found between LDS and non-LDS, but both groups had mortality rates below U.S. expectation. Although recent studies hare reported smoking to be a risk factor for CBVD, we found no consistent difference between the LDS and non-LDS, eren in the younger age groups. The results do not support the hypothesis that tobacco is an important etlologic agent in CBVD mortality.