The association between glutathione S-transferase pi (GSTπ）and other clinicopathological parameters, response to chemotherapy and clinical outcome were investigated in chemotherapy naive epithelial ovarian cancer patients. Paraffin-embedded material from 55 patients were used for immunohistochemical analysis. All patients had received six cycles of cisplatinum-based chemotherapy and 41 of them were revalued by laparotomy. Pre- and post-chemotherapy GSTπ staining were detected in the cancer tissues of 18/55 (32.7%) and 5/14 (35.7%) patients, respectively. GSTπ expression was not associated with other clinicopathologic para­meters. Of 17 patients with postoperative measurable residual disease clinical response was observed in 4/7 of GSTπ positive and in 9/10 GSTπ negative patients (p = 0.25). Pathologic complete response (pCR) was achieved in 5/8 of GSTπ positive and 11/22 of GSTπ negative cases (p = 0.69). There was no significant difference in overall survival and progression-free survival (PFS) according to initial GSTπ status. However the PFS of the five patients (median 22 ± 5.9 months) who had postchemotherapy positive GSTπ was significantly shorter than the nine patients (10.0 ± 2.19 months) who had negative GSTπ(p = 0.006). This difference was not observed in overall survival. These results suggest that initial immunohistochemical staining of GSTπ does not aid in the prediction of pCR and clinical outcome in patients with epithelial ovarian cancer. Nonetheless investigation of GSTπ expression after chemotherapy needs further evaluation.