The aim of this study is to determine the expression levels of GST isoenzymes in salivary gland pleomorphic adenoma from 26 patients. In this study, we investigated the immunohistochemical staining characteristics of the Glutathione-S-transferase alpha (GSTA-1), sigma (GSTS-1), theta (GSTT-1), kappa (GSTK-1), mu (GSTM-1), omega (GSTO-1) isoenzymes in tumor and surrounding tumor-free (normal) salivary gland tissues from 26 patients. For immunohistochemical studies, tissues were obtained from 26 patients with salivary gland pleomorphic adenoma (PA). Tumor and control tissues of patients were compared according to their staining intensity. The correlations between GST expressions in PA tissue were analyzed by Spearman’s rho and the clinicopathological data were examined by Mann Whitney-U test and Spearman’s rho. Considering the differences in the expressions of GST isoenzymes between tumor tissues and normal tissues of the patients; No differences in GSTT1 and GSTS1 isoenzymes expression were found between tumor and normal tissues (p>0.05). GSTM1 and GSTO1 expression were significantly higher in tumor tissues than in normal tissue. However, GSTK1 and GSTA1 expressions were found to be significantly higher in the normal tissues of the patients compared to the tumor tissues. GSTM1 and GSTO1 expressions were increased in salivary gland PAs. These results should be confirmed with a larger series and different enzyme subtypes.