Immunohistochemistry is a well-established technique used in many research laboratories as well as in clinical diagnostics. The method allows to visualize the expression of proteins in biological tissues, as well as to evaluate this expression semi-quantitatively. For diagnosis, an optimal staining, based on a straightforward protocol, is crucial. In many sudden cardiac death cases, immunohistochemistry is the only tool enabling the diagnosis of myocardial ischemia/infarction, thus the diagnosis of the cause of death. Improvements in immunoreactions are actually possible thanks to optimized detection systems. The recently introduced detection system EnVision Flex™ by Dako allows to dramatically improve (in terms of intensity of the signal and practically absence of background) the visualization of antigens in formalin-fixed paraffin-embedded (FFPE) tissue sections. We tested this method for the detection of myoglobin and troponin T in human postmortem cases of myocardial infarction, as the results obtained by using the « classical » ABC (avidin-biotin complex) method have proven to be sub-optimal, thus rendering any interpretation very difficult, if not impossible.