Background: Pesticides are widely used in agriculture for the crop protection. Despite advanced mechanization of the agricultural production, the population’s exposure to these chemicals is still significant. The objective of the study was to evaluate farmers’ occupational exposure to two most frequently used pesticides: MCPA and 2,4-D. Material and Methods: Pesticide exposure was assessed in 24 farmers, living in the Łódź voivodeship agriculture area, for 71 sprayings performed on their arable areas. The exposure assessment methods were used to estimate workers’ exposure to selected pesticides (MCPA and 2,4-D). The analysis covered the biological material (urine) collected on the day of pesticides spraying: in the morning before spraying (Sample A), in the evening after spraying (Sample B) and on the next day (Sample C). Results: The level of pesticides found in farmers’ urine was growing from sample A to sample C. The highest level of pesticides was found in sample C and the lowest in sample A. The predictors of the pesticide level were: sample collection time (urine concentration of pesticides in sample C compared with sample B) (p = 0.002), concentration of pesticides in sample A (p = 0.012) and the amount of products used during spraying (p = 0.021). The use of protective equipment was at the border of statistical significance (p = 0.059). The differences in exposure between farmers can be only partly explained by the analyzed exposure predictors. Conclusions: The study not only confirmed the presence of occupational exposure but also showed the level of exposure among farmers under study. This is very important because in Poland the level of exposure among farmers is unknown and studies using the biological monitoring are very rare.