Abstract: AIM: To observe the effect of electroacupuncture (EA) preconditioning on cognitive dysfunction in patients undergoing heart valve replacement surgery and coronary artery bypass grafting (CABG) with cardiopulmonary bypass under general anesthesia. METHODS: One hundred and six patients (49 males, 57 females) were randomly allocated to EA preconditioning group and control group. EA preconditioning group was treated at bilateral Neiguan (PC 6), Lieque (LU 7) and Yunmen (LU 2) with electrical stimulation (5-30 Hz, 2.34-6.24 mA, 30 min) for 5 consecutive days before heart valve replacement surgery and CABG. Before operation and 7 days and 14 days after operation, all patients were required to undergo a battery of five neuropsychological tests including mini-mental status examination, digit span test, digit symbol test, trial-making test and short-story memory test. RESULTS: A total of 75 patients completed the tests (38 in EA group and 37 in control group). No significant differences were found in age, gender, height, weight and educational level between groups. The incidence of postoperative cognitive dysfunction in EA group and control group was 26.3% and 24.3% 7 days after operation, and 10.5% and 13.5% 14 days after operation, respectively. Statistical analysis showed no significant difference between groups. CONCLUSION: EA preconditioning has no effect on the incidence of cognitive dysfunction in patients to be treated with heart valve replacement surgery and CABG with cardiopulmonary bypass under general anesthesia.