The addition of fluorescent tracers to agricultural spraying systems allows the direct evaluation of protective clothing under actual field conditions. Deposition of the tracer beneath clothing is quantified by means of a video imaging system. Workers are illuminated under long-wave ultraviolet light following exposure, and the fluorescence on the skin is measured. This exposure assessment technique was tested with 25 workers conducting mixing and high-volume airblast application procedures with the organophosphate pesticide malathion in citrus groves. Three types of protective clothing were compared: cotton/polyester workshirts, cotton/polyester coveralls, and nonwoven coveralls (untreated Tyvek). All workers had measurable hand exposure, despite the use of neoprene gloves. Hand exposure to mixers was more than twice that of applicators. Substantial deposition of tracer occurred beneath clothing. The applicator group wearing workshirts was more highly exposed than either of the coverall groups (Analysis of Variance, p < 0.05). Exposure between the two coverall groups did not differ significantly for either mixers or applicators. The heaviest depositions for the coverall groups occurred near the openings of the garments (collar and sleeves), suggesting that studies of penetration through fabric do not provide a complete evaluation of potential exposure under field conditions. This study demonstrates that fluorescent tracers and video imaging can be used to provide a quantitative index of protective clothing field performance.