Equine metabolic syndrome (EMS) is a metabolic disorder characterized by excessive obesity and or/regional adiposity, insulin resistance (IR) and prior or current laminitis. In the course of the EMS, an important role exert systemic inflammation caused by excessive expression of proinflammatory cytokines. The aim of the current investigation was to examine relationships between expression IL-6 and TNF-alpha in adipose tissue and their concentration in peripheral blood in horses with EMS. On the basis of range of research procedures, horses were divided into two groups: group A (EMS horses, n=8) and group B (healthy horses with overweight, n=8). The concentration of the proinflammatory cytokines in the peripheral blood and their expression in the adipose tissue were determined. The results of the EMS group showed numerous macrophages and lymphocytes infiltration and increased diameters of adipocytes (P<0.05). The concentration of TNF-alpha in the serum of insulin-resistant horses was statistically higher compared to the healthy individuals. No significant differences were observed between the EMS horses and the control horses in the concentration of IL-6 in the serum. Moreover, our research revealed expression of investigated cytokines in adipose tissue. The results shows a higher expression of TNF-alpha in the EMS groups. What is more, macrophages infiltration were observed. In the case of IL-6, were detected the similar arrangement of this cytokines in adipocytes between both test groups. The study indicates the importance of pro-inflammatory proteins TNF-alpha in the equine metabolic syndrome.