Objective: Farming is associated with exposure to a wide variety of risk factors including organic dusts, endotoxins, allergens and other chemicals. The ability of some of these agents to interact with the immune system is demonstrated in the presented study which was undertaken to evaluate the relationship between pig and cow breeding, and the immune system early changes. Particular attention is paid to selected serum cytokines. Methods: Sixty four animal breeders (36 cattle and 28 pig breeders) were selected as the exposed group, and 32 rural workers not engaged in animal breeding were utilised as the controls. Personal data were collected through a questionnaire, and selected serum parameters measured, including cytokines IL-6, IL-8, IL-10, IFNγ and TNFα, immunoglobulins and proteins, and total and differential white blood cell counts. Results: The study stresses the significant increase of TNF-α, IL-8, and IL-10 in animal breeders, with the highest values in pig breeders, and a slight but statistically significant increase in albumin and total serum proteins.Conclusions: The findings of the presented study suggest a condition of immune system activation in animal breeders, with the highest levels observed in pig breeders. These changes may be attributable to exposure to organic dusts, endotoxins, or to the different biological agents present in the rural environment. The prognostic significance of these findings, however, remains unclear, but the observed changes might be indicative of a risk of developing respiratory toxic and allergic diseases, which need to be further investigated.