Earlier toxicology studies found that one strain of rat (Long-Evans) developed severe ocular lesions when fed high doses of alachlor, a chloracetanilide active ingredient in some preemergent herbicides used for corn, soybean, and peanut crops. Because of a lack of eye effects in feeding studies conducted in dogs and other rodent species and strains, the effect was believed to be specific to Long-Evans rats. Nevertheless, to determine whether there were ocular effects among alachlor-exposed workers, we examined a group of the highest exposed alachlor production workers (n = 135) for the presence of a specific eye abnormality, analogous to the initiating lesion in Long-Evans rats, called pigmentary dispersion syndrome. A similar examination was given to unexposed coworkers and relatives (n = 84) to provide comparison rates. None of the exposed workers were found to have pigmentary dispersion syndrome, and prevalence rates for other eye abnormalities were similar for exposed and unexposed study participants. These results suggest that humans exposed to alachlor are not at increased risk of developing ocular disease.