The study was conducted to verify a reduction in mortality from tumors in dairy farm workers, exposed to endotoxins, which increase in the host a cytotoxic antitumoral. From the SCAU files of the Province of Padova, we selected 2.415 subjects with informations on: date of hire, date of work termination, number of dairy cattle, area of the farm. The vital status was ascertained through the Communes of residence, and for the 541 decedents the cause of death was established. The standardized mortality ratio (SMR) was calculated on the basis of age-sex-cause-calendar period specific mortality rates in the Veneto. In the 1.641 dairy farm workers, SMRs were significantly low for total tumors (= 81) and lung tumors (= 66), and significantly high for brain tumors (= 283). In other 774 farmers, no significant SMRs were observed. The data will be further processed to verify a dose-response relationship with the occupational risk indicators. Smoking habits will be collected.