Appliant's Astract). The principle objective of this study is to evaluate the effect of specific agricultural exposures on the risk of Parkinson's disease. Other potential risk factors will be investigated to allow correction for potential confounding or because some agricultural exposures may have been overlooked as a result of the focus on paraquat chemicals. Specific factors to be investigated are: 1) farm and non-farm exposure to pesticides (including herbicides, insecticides, fungicides, and rodenticides); 2) occupational exposures (farm and non-farm) to other agents, including fertilizers, animal-related exposures, specific solvents, fuel and engine exhaust, lubricating and hydraulic fluids, polycyclic aromatic hydrocarbons, lead, wood preservatives, and paints; 3) medical history including head trauma; 4) genetic syndromes and familial clustering, including both PD and other degenerative neurologic disease; and 5) tobacco and alcohol use. The design will be a population-based case-control study, with 300 recently diagnosed PD cases frequency-matched by age and sex to 600 controls. The geographic region of interest is the 66 counties of eastern Nebraska, an extensive agricultural region with a variety of crops, highly stable population, and a very low refusal rate to epidemiological studies. Exposure will be assessed by computer-assisted telephone interview by a professional survey corporation, having extensive previous experience with survey instruments in case-control studies of various cancers in the eastern 66 counties of Nebraska.