Occupational environment of farmers is full of biohazards. Especially frequent are molds found in grain, grain dust, and soil. People might be affected by diseases caused by these molds inducing: skin infections, bronchial asthma, allergic rhinitis and others.The aim of the study was to detect and quantify colonization by molds in samples of grain and grain dust collected during combine threshing, as well as in soil samples from organic and conventional cultivation systems in south – east Poland. The following were used for the study: 20 samples of rye, wheat and barley grain, 20 samples of every grain dust collected during combine threshing and 20 samples of soil for every cereal were collected from an organic cultivation system. The same number of corresponding samples from a conventional system of farming was also obtained. The concentrations (CFU/g) of molds were determined applying the method of plate dilution on two media, and the species composition of molds was determined using taxonomic keys and atlases. The results show a potential risk for people engaged in agriculture. The presence of allergenic and toxigenic molds in the work environment of this working group creates serious occupational exposure. This subject is of high significance for the health of population engaged in agricultural production and calls for further studies.