The paper is focused on analysing the principles of biosecurity preventive measures as a basis for prevention of penetration of African swine fever (ASF) virus into the pig farms processed on the basis of Czech and foreign literary sources. The basic measure to prevent the spread of AMP is to comply with the principles of biosecurity in all farming systems and stages of pig breeding. The feasibility and effectiveness of preventive measures depends primarily on the pig farming system and the farm size. In small-scale and organic pigs breeding units with pig access to outside runs or grassland, there are only limited possibilities of introduction and keeping the general principles of biosecurity. In large-scale pigs breeding units are the principles of biosecurity an integral part of good husbandry practices.