Carbon monoxide poisoning is the leading cause of mortality and morbidity of toxic origin in the world. Its insidious and polymorphic symptomatology makes it difficult to diagnose. It occurs accidentally, because of non-supervised domestic fires, or in fire victims. In fire victims, in particular, the differential diagnosis between carbon monoxide gas poisoning, inhalation of other toxic products of combustion like cyanide, oxygen deprivation, thermal burns and shock due to burns as a cause of death is not an easy task. The authors examined 107 fire victims that were autopsied at the Forensic Medicine from Iasi, Romania, in the last 10 years (2007-2016). Most cases were males (69.16%), young (0-9 years) or older than 60 with a burned surface of 91-100% in 68.22% of cases. Blood samples from the cadavers were collected in all cases in order to analyse carboxyhaemoglobin concentration and haemolysis. Toxicological analysis revealed a carboxyhaemoglobin level of maximum 95% but the majority of cases (70.72%) had a concentration inferior to 50%. An inverse correlation was identified between carboxyhaemoglobin concentration and haemolysis, an indicator of heat dissociation. Our study proves that many fire victims may die because of carbon monoxide intoxication prior to the extent of burns at a lethal potential.