A cohort study of agricultural practices and the mortality experience (1971 to 1987) of male farmers in Manitoba, Saskatchewan, and Alberta has been conducted. The census records of 156, 242 male farmers identified on the 1971 Census of Agriculture and the corresponding Census of Population were linked to mortality records through 1987. We observed associations between multiple myeloma mortality and fuel/oil expenditures (relative risk for top quartile of exposure = 1.69, 95% confidence interval = 1.08 to 2.65). No significant associations were found between multiple myeloma and herbicide use or with selected sociodemographic variables.