The interpretation of deaths occurring in fires is often complicated by numerous tissue artefacts. The aim of this experimental study was to see whether coronary arteries exposured to heat may have altered morphology. Two specimens of coronary arteries were taken from each of 10 previously healthy men, who died due to trauma, who had no macroscopic evidence of coronary atherosclerosis – one specimen was immediately fixed in formalin (control group), while the other was exposed to high temperature (70°C for five minutes), and then fixed (experimental group). Morphometric analysis of arterial walls showed significant thickening of about 45 % in tissue samples from the experimental group (control vs. experimental: 604.8μm vs. 879.2μm, p50 %), compared to the tunica media (4%). Another feature was either partial or complete loss of the internal elastic lamina in all of the heated arteries. The results of the current study suggest that the morphology of coronary arteries in cases of fire-related deaths should be carefully interpreted, since the thickness of their wall could be increased not due to underlying disease states, but simply due to heat exposure, which may lead to inaccurate pathological interpretations. This may have considerable medicolegal significance if a deceased driver or pilot is being assessed for liability in an accident.Copyright © 2020. Published by Elsevier B.V.