Cardiac ischemia-reperfusion experiments in the mouse are important in vivo models of human disease. Infarct size is a particularly important scientific readout as virtually all cardiocirculatory pathways are affected by it. Therefore, such measurements must be exact and valid. The histological analysis, however, remains technically challenging, and the resulting quality is often unsatisfactory. For this report we have scrutinized each step involved in standard double-staining histology. We have tested published approaches and challenged their practicality. As a result, we propose an improved and streamlined protocol, which consistently yields high-quality histology, thereby minimizing experimental noise and group sizes.