Objective To investigate the forensic applicability of nuclear factor-kappa B p65 (NF-?B p65) to the diagnosis of early myocardial ischemia in cases of sudden cardiac death. Methods The cases were divided into three groups: the cases with early myocardial ischemia, myocardial infarction and cases used as control. Immunostaining of NF-?B p65 was performed by SP method in cardiac tissues. The intensity of NF-?B p65 was observed under light microscope and analyzed semi-5quantitatively. Results NF-?B p65-positivecardiac cells were detected in cytoplasm and nuclei in the cases with early myocardial ischemia and myocardial infarction, and the intensity of immunoreactivity was approximately the same. No positive immunostaining was found in the control cardiac tissues. Conclusion The results suggest that the early myocardial ischemia may have revealed as the same changes as myocardial infarction at molecular level, indicating that NF-?B p65 may be used as a marker for postmortem diagnosis of the early acute myocardial ischemia by immunohistochemical technique.