This contract will support a prospective epidemiological study of cancer among farmers and their dependents and other pest control workers. The study will establish a large cohort to be followed prospectively for 10 years or more to obtain detailed information on agricultural exposures, diet, cooking practices, and other factors of etiologic interest for cancer and other diseases. The cohort will include men and women who are either farm owners/operators, their spouses and dependents, or commercial or non-commercial pesticide applicators. The work will be carried out by one Coordinating Center and two Field Stations, each supported under separate contracts. This contract will establish a Field Station in the state of Iowa to select pesticide applicators for inclusion in the cohort, to collect data from pesticide applicators, to monitor cancer incidence and mortality in the portion of the cohort in the state of Iowa, and to fulfill the goals of the study, i.e., to evaluate cancer risks among farmers producing grains and livestock. This five-year study is being conducted by the Office of the Associate Director (OAD), Epidemiology and Biostatistics Program (EBP), Division of Cancer Etiology (DCE), National Cancer Institute (NCI) to explain why farmers experience an excess of several cancers.