Mormons have been shown to have low cancer rates at several common sites, particularly those associated with tobacco and alcohol use. This likely reflects adherence to their Church doctrines advocating abstention from the use of these substances. All Mormons, however, do not adhere to the health practices of their Church, and this study classifies Utah Mormon men by their lay priesthood offices, which reflect degree of adherence to Church doctrines. Follow-up cancer rates for 1966-1970 indicate that the most devout group (Seventies and High Priests) have lung cancer rates 80% lower than those of the least devout group. The same was seen for all smoking- and alcohol-associated cancer sites combined. Cancer of the stomach and the leukemias and lymphomas also had lower rates in the most devout group. Cancers of the colon-rectum, prostate, and pancreas showed little difference in rates when classified by lay priesthood office. These data provide a demonstration of the effects of a healthy lifestyle on cancer occurrence in men.