We aimed to assess the effect of exposure to pesticide on platelet indices including mean platelet volume (MPV) and platelet distribution width (PDW) in farm workers. The study group consisted of 40 farm workers (4 females, 36 males; mean age 42.6 ± 9.8 years). An age-, gender- and body mass index-matched control group was composed of 38 healthy volunteers (8 females, 30 males; mean age 46.1±8.9 years). Platelet indices were assessed in farm workers exposed to pesticides. MPV values were significantly lower in farm workers than in those of controls (6.3 ± 1.1 vs. 7.6 ± 0.7 fL, respectively; p < 0.001). Platelet count was significantly lower in farm workers than those of controls (155.7 ± 35.7 vs. 271.3 ± 96.2 × 10(9)/L, respectively; p < 0.001). PDW was significantly lower in farm workers than in those of controls (8.9% ± 2.0% vs. 15.8% ± 0.8%, respectively; p < 0.001). We have found that MPV and other platelet indices were significantly lower in farm workers exposed to pesticides than those of controls. Our findings suggest that MPV may be a sensitive indicator of a pesticide-exposure effect.