High levels of inflammatory cytokines were proposed contributors to the pathogenesis of a various inflammatory skin disorders. Therefore, investigating the immune response of the inflammatory skin disorder allows a better understanding of pathogenesis of a various inflammatory skin disorders and therapeutic approaches. The aim of this study was to analyze of the immune response in dogs with chronic inflammatory skin disease. To this aim, the present study evaluated relative mRNA expression of canine $IFN-{gamma}$, IL-4, $TGF-{eta}$ and IL-10 using TaqMan realtime PCR assays and semi-quantitative RT-PCR in freshly isolated peripheral blood mononuclear cells from twenty dogs with chronic inflammatory skin disease and ten normal dogs. The relative mRNA expression levels of IL-4 mRNA were significantly higher in dogs with chronic inflammatory skin disease than those in normal dogs (P < 0.01). The results of present study also showed a tendency towards increased expression of IL-10 transcripts in dogs with chronic inflammatory skin disease. However, there were no significant differences in the levels $IFN-{gamma},;TGF-{eta}$ between normal and chronically inflammed dogs. In addition, the concentration of serum IgE was significantly increased in dogs with chronic inflammatory skin disease compared with those in normal dogs (P < 0.01). In histopathological examination, we found that there were markedly increased mast cell counts in chronically inflammed dogs (P < 0.05). These results suggest that the pathogenesis of chronic inflammatory skin disease might be associated with a T-cell mediated inflammatory responses characterized by a Th2-skewed immune response. Based on these results, the modulation of Th1/Th2 balance may be an effective therapeutic strategy for the treatment of chronic inflammatory skin disease.