Tests of pulmonary function (FVC, FEV1, FEV 1%, and single breath CO diffusion), renal function (serum creatinine and BUN), liver function (serum ALT, AST, and ALKP) and a full haematological screen were performed on 27 paraquat spraymen (mean spraying time 5.3 years; mean individual annual quantity of paraquat handled, 67.2 kg as paraquat ion) and on two control groups. One of the control groups consisted of 24 general plantation workers with minimal exposure to paraquat arising from occasional work in recently sprayed areas, and the second consisted of 23 latex factory workers with no known occupational exposure to paraquat. The results showed no significant differences as a consequence of occupational exposure to paraquat. Long-term paraquat spraying at the concentrations used produced to quantifiable harmful effects on health as measured by the indices selected for this study.