The major hazardous factors of the labour conditions in modern poultry farms are presented by dust mixtures including both vegetable and organic substances, biologically active substances and microorganisms, gaseous products, as well as unfavourable microclimate conditions and physical overload. Detailed medical examinations of poultry farmers revealed dependence of respiratory and pulmonary diseases, cardiovascular and nervous disorders on the labour conditions, the major etiologic factor being such allergens as feathers, down, blood serum, poultry excrements, bacteria and fungi.