Objective:To investigate the expression and clinical significance of Treg markers in CD8+ T cells from peripheral blood and tumor tissues of ovarian cancer patients. Methods: Flow cytometry was used to detect the percentage of Foxp3, CD25, CD28, CTLA-4 and GITR in CD8+ T cells in tissues from 12 benign ovarian tumor patients, 14 ovarian cancer patients, in peripheral blood from 31 patients with ovarian cancer, 31 patients with benign ovarian tumor and 31 healthy volunteers. Results: Flow cytometry revealed that the expressions of Foxp3 and CTLA-4 in CD8+ T cells of ovarian cancer tissues were higher than those of benign ovarian tumor tissues (P < 0.05); The expression of CD28 in CD8+ T cells of ovarian cancer tissues was significantly lower than that of benign ovarian tumor tissues (P < 0.01); The expressions of Foxp3, CD25 and CTLA-4 gated on CD8+ T cells in peripheral blood of ovarian cancer patients were significantly higher than those of patients with benign ovarian tumor and healthy control subjects (P < 0.05), the expression of CD28 gated on CD8+ T cells in peripheral blood of ovarian cancer patients was significantly lower than that of patients with benign ovarian tumor and healthy control subjects (P < 0.05). Conclusion: Frequency of CD8+ Treg in ovarian cancer patients was higher than benign ovarian tumor patients and healthy controls. The expression of Foxp3 in CD8+ T cells in peripheral blood of ovarian cancer patients correlated with tumor stage, suggesting Foxp3 could be used as an important indicator of ovarian cancer progression.