The mortality pattern of Seventh-Day Adventists (SDAs) in the Netherlands was assessed during a ten-year study period, 1968–1977. Of 522 deceased SDAs the causes of death of 482 could be ascertained. Standardized Mortality Ratios (SMR) for total mortality (SMR = 0,45), cancer (SMR = 0,50) and cardiovascular diseases (SMR = 0,41) as well as for various subgroups differed significantly from the total Dutch population. Mean age at death as well as life-expectation at baptism were significantly higher in SDAs, both in males and females, as compared with Dutch males and females. A health survey among a sample of the total SDA population and a group of ‘friend’ controls was done in order to try to explain the differences in mortality pattern and life expectancy. It is concluded that evidence was found for the thesis that abstinence from cigarette smoking is the main factor explaining the low mortality from ischaemic heart diseases among SDAs, while presumably an appropriate (prudent) diet confers additional benefit for example on colon cancer mortality.