In a study of the mortality of Ontario undertakers, a cohort of 1,477 men first licensed during 1928 through 1957 was followed up until the end of 1977. Numbers of observed and expected deaths were determined for the period 1950 through 1977, using mortality rates of Ontario men as the standard. In all, 319 persons had died, compared with 322 expected. Ontario undertakers were not at increased risk of death from cancers at sites of contact with formaldehyde. Cirrhosis of the liver (standardized mortality ratio, 238) and chronic rheumatic heart disease (standardized mortality ratio, 199) were the only causes of death found to be significantly in excess. The data are discussed in the context of current epidemiologic information on the mortality experience of persons exposed to formaldehyde.