Canine babesiosis is a tick-borne disease with world-wide significance caused by intraery-throcytic protozoa of the genus Babesia. The eicosanoids, as inflammatory mediators, areinvolved in the regulation of the immune response and inflammatory reaction. Metabolismof lipids is of great importance in babesiosis. In this study it was aimed to investigatethe dynamics of serum concentration of prostaglandin E2(PGE2), thromboxane B2(TxB2),leukotriene B4(LTB4), triglycerides, total cholesterol (Chol), HDL- and LDL-cholesterol indogs naturally infected with Babesia canis and healthy dogs. Both groups were measuredfor all parameters on the admission day and on the first, second and seventh day of thedisease. Dogs that were included in this study had systemic inflammatory response syn-drome (SIRS) and multiple organ dysfunction syndrome (MODS). It was demonstrated thatthe level of LTB4, PGE2, TxB2in dogs naturally infected with B. canis significantly changedduring the disease. The level of LTB4was significantly higher during the study, while theconcentration of PGE2was significantly higher second, third and seventh day of disease inrelation with healthy dogs. The level of TxB2was significantly lower at the beginning of thedisease, but after seven days concentration was significantly higher. Both group of patientswith SIRS and MODS had significantly higher level of LTB4. Substained high concentrationsof PGE2were observed in dogs with MODS after therapy but not in dogs with SIRS, andLTB4followed a similar tendency. On the other hand, increases in TxB2were only signif-icant in dogs with SIRS. The lipid profile in naturally infected dogs with B. canis infectionwas significantly changed. Further studies are needed to assess the prognostic values oflipid mediators in dogs with B. canis infection, and the ability of these markers to predictthe progress of SIRS and MODS