Epithelial-mesenchymal transition (EMT), as defined by loss of epithelial characteristics and gain of a mesenchymal phenotype, has been reported in human and canine mammary tumors, but similar study in feline mammary tumors has not been performed. EMT can be induced or regulated by various growth and differentiation factors among which TGFβ has received much attention. The aim of our study was to evaluate loss of epithelial and gain of mesenchymal markers in epithelial neoplastic cells of feline mammary tumors and to assess possible correlation with expression of TGFβ. A total of 27 feline mammary gland hyperplastic and neoplastic lesions were selected from archive of Department of veterinary pathology Zagreb (4 benign lesions, 3 grade I carcinomas, 8 grade II and 12 grade III carcinomas) to evaluate immunohistochemical expression of cytokeratin AE1/AE3, E-cadherin, vimentin and TGFβ. One-way ANOVA with post hoc Tukey's test and Spearman's rank correlation coefficient were used for statistical analysis. Generally, loss of cytokeratin and E-cadherin, and gain of vimentin were more frequently observed in carcinomas of higher malignancy grade compared to benign lesions. However, the correlation between each marker showed only positive correlation between loss of E-cadherin and gain of vimentin (r= 0.69, p< 0.05) in grade II carcinomas. The expression of TGFβ was significantly higher in carcinomas grade II and III compared to grade I (p< 0.05). These findings indicate occurrence of characteristic changes suggestive of EMT in feline mammary carcinomas and a possible role of TGFβ in this process.