Objective  To optimize the cutoff value of ELISA for the detection of hepatitis B core antibody IgM. Methods  Three hundred and seventy-two specimens were tested by two methods, ELISA and chemiluminescence immunoassay (CLIA). The results were analyzed using Receiver Operating Characteristic (ROC) curve to determine the optimized cutoff values, and then statistical analysis was performed on the results before and after optimization. Results  CLIA results were 129 positive and 243 negative. ELISA results at cutoff value of 0.105 were 230 positive and 142 negative. Kappa test showed a moderate agreement between the results of the two methods (Kappa=0.49, P<0.001). The ROC curves were analyzed and the best cutoff value of 0.296 was obtained. Specificity, correctness index, and agreement rate were better than those at cutoff value of 0.105, except for a slight decrease in sensitivity. Kappa test showed a high level agreement between the results of the two methods rose to (Kappa=0.85, P<0.001). Conclusion  The results of ELISA and CLIA are in better agreement with the cutoff value of ELISA set at 0.296.