The effect of general or epidural anesthesia on immune system is not well-known for the patients whose immunity have been supressed by uremia. The aim of our study was to evaluate the effect of general and epidural anesthesia on T cell, natural killer cell and complete blood count in patients undergoing renal transplantation. After ethics committe approval, 29 patients undergoing renal transplantation were included in the study. Anesthesia was induced with thiopental, fentanyl, atracurium and maintained with isoflurane, N2O and O2 in the general anesthesia group (Group G, n=15). In the epidural anesthesia group (Group E, n=14) epidural catheter was inserted and 20 mL 2% prilocain and 100 µg fentanyl was given. 1% prilocain and 2.5 µg/mL fentanyl (7 mL/hr) were infused for maintanence. Complete blood count, leukocyte subgroups, CD 3 (T cell marker), CD 16/56 (NK cell marker), BUN, creatinine, Na+ and K + levels were studied on preoperative, intraoperative and postoperative 1st and 3rd days in both groups. Statistical analyses were performed with Mann Whitney U, chi-square and Wilcoxon tests. Demographic data were similar in both groups. In Group E leukocyte count on postoperative 1st day was significantly higher, Hb and Hct levels on postoperative 3rd day were significantly lower than Group G. No significant difference was found for CD 3, CD 16/56, BUN, creatinine, Na+ and K+ levels between the groups. General and epidural anesthesia have similar effects on complete blood count, leukocyte subgroups, T cell count, NK cell count, BUN, creatinine, Na+ and K+ levels in patients undergoing renal transplantation.