We surveyed 1,000 randomly selected state-licensed pesticide appliers to improve our understanding of pesticide use and its potential health effects. Participants were stratified by pesticide class (herbicides, insecticides, fungicides, fumigants) to determine potential differences in health characteristics among different pesticide groups. A subset of 60 applicators, divided by pesticide class used, were studied for exposure-related cholinesterase (ChE) depression. ChE depression in excess of 20% was most frequent in fumigant applicators who did enclosed-space application, in addition to other pesticide application procedures (p < .05). Survey data demonstrated that the prevalence of all common chronic diseases considered together was significantly increased (p = .015) in fumigant appliers, compared with all other pesticide use groups. The frequency of chronic lung disease was also significantly increased in the fumigant applier group (p = .027). Curiously, two cases of a rare hematopoietic neoplasm--hairy cell leukemia--were identified in our study group (annual incidence 0.67/100,000 in Minnesota). Whether there is an association between this unique tumor and agricultural work is uncertain, and further study is needed in this regard.