The mortality experience among 22,938 white males who were enrolled in the life insurance program of the American Federation of Grain Millers was assessed for the period 1955 through 1985 in a cohort mortality analysis and in a nested case-control analysis. Significantly fewer deaths were observed among this group than expected for all causes of death combined [standardized mortality ratio (SMR) = 89] compared with the number of deaths observed among the general population of U.S. white males of the same age. Excess risks for developing non-Hodgkin's lymphoma (NHL) (SMR = 149), leukemia (SMR = 136), and pancreatic cancer (SMR = 133) were restricted to workers employed in flour mills, where pesticides are used more frequently than in other segments of the industry. In the nested case-control analysis, excess risks for developing these cancers were also observed in these workers, but the relative risk for developing NHL [odds ratio (OR) = 4.2] was approximately twice that for developing pancreatic cancer (OR = 2.2) and that for developing leukemia (OR = 1.8). Within the flour mills, the workers who had ever worked in the maintenance department (OR = 8.1) or in the elevator department (OR = 2.8) were at particularly elevated risk of developing NHL, suggesting that exposures in these departments should receive further attention.