Adequate hygienic level of rearing environment is the presumption of achievement of the production and reproduction potential of the farm animals and the profitability of the farm. The aim of this work was to develop a simple system for assessing the impact of microclimate and breeding technology to the level of biosecurity on the basis of a comprehensive analysis of selected factors of rearing environment. There was designed a system of comprehensive evaluation of selected factors (vectors, equipment, housing, food, water, cleanliness, rearing environment) that affect the possibility of penetration and spread of pathogens in farm animals. Quality of the rearing environment and the technology of housing significantly influence the biological safety of farm animals.