A case-control investigation was conducted to evaluate the hypothesis that past exposure to the pesticide lead arsenate led to an excess mortality from respiratory cancer. Cases included all white male orchardists who died in Washington State between 1968 and 1980 from respiratory cancer. Orchardists who died of other causes during this period served as controls. Occupational and smoking data for 155 case subjects and 155 control subjects were obtained via telephone interview with next-of-kin/informants. Neither presence, intensity, nor duration of lead arsenate exposure differed between case and control subjects. Although cigarette smoking was unusually common among cases of respiratory cancer, smoking habits of the orchardists and a sample of non-orchardists who had died of other causes were quite similar. The cause of the excess mortality from respiratory cancer among Washington State orchardists remains unknown.