This study was conducted to determine the concentrations of cytokines, interleukin (IL)-1β, IL-1 receptorantagonist (ra), IL-6, interferon (IFN)-γ and tumor necrosis factor (TNF)-α in serum and whey from clinicallyhealthy cows and cows with peracute coliform mastitis, and to evaluate the association of increased cytokinelevels in mastitic cows with their clinical findings. The concentrations of IL-1β, IL-6, and IFN-γ in serumand whey from E. coli mastitic cows at the onset of mastitis were apparently increased, compared with thoseof healthy cows. Increased levels of cytokine concentrations in whey were reduced during the mastitis recoveryprocess of. Correlations were found between increased levels of IL-6 in serum and whey and IFN-γ inwhey and their characteristic findings in E. coli mastitic cows at the day of diagnosis. These findings suggestthat increased levels of cytokine concentrations in dairy cows with E. coli mastitis may be associated with thepathogenesis and their characteristic findings.