Abstract: Objective To evaluate the effect of perioperative HLA antibody changes on acute allograft rejection in cadaveric liver transplantation. Methods Totally 134 patients received modified piggyback liver transplantation and enzyme-linked immunosorbent assay was performed for HLA antibody detection before and the 1, 7, 14 and 30 days after operation. B ultrasound-guided liver biopsy was employed for diagnosis of acute allograft rejection, and the perioperative changes of HLA antibodies were evaluated for their effect on allograft acute rejection. Results Of the 44 recipients with preoperative positivity for HLA antibodies, acute rejection occurred in 56.8% of the patients, as compared with 25.9% in those negative for HLA antibody (P=0.001). The patients who became positive for HLA antibody postoperatively had a rate of acute rejection of 60%, which was significantly higher than that in those persistently negative for HLA antibody (18.6%, P=0.003). Conclusion HLA antibody positivity before transplantation may contribute to acute rejection episode in liver transplantation, and persistent posttransplant HLA antibody positivity is closely associated with the occurrence of acute rejection.