Two different groups of workers, involved in production or formulation of chlorotriazine herbicides during the last 10 years, have been retrospectively studied for occurrence of diseases related to the exposure to Atrazine, Simazine, Propazine, and Terbuthylazine. A control group has been selected between clerical workers of the same plants. Subjects exposed to the different compounds have been studied for inhalator and dermal exposure by active sampling, skin pads, and hand washings; samples have been further processed and specifically analysed. Urines have been studied for the presence and concentrations of mono and bidealkylated triazine metabolites. Exposure data have been collected during the last five years and extrapolations have performed for exposures in the preceding years. Clinical finding and laboratory data for all workers have been obtained from medical surveillance records. Data available for the last 10 years have been evaluated to highlight possible differences between the investigated groups.