The medicolegal importance of ischaemic heart disease and myocardial infarction is summarized and discussed. Some theories of pathogenesis and aetiology of ischaemic heart disease, specially those which are more important and relevant to the medicolegal practice, are discussed. Results of the study of 33 cases of coronary artery atherosclerosis and myocardial infarction at different stages of development are presented. The condition of the coronary arteries and the myocardium is examined on gross and microscopical levels. Pathological findings are correlated with the clinical data obtained from the case histories and the summaries of the necropsy requests. No good correlation exists between the observed pathological changes and the clinical age of the infarction and, in most instances, the latter appears younger than the age estimated on the pathological ground alone. As far as the age of the infarction is concerned, most special histochemical staining methods are not preferable to the routine haematoxylin and eosin method. However, the former are efficient in demonstrating and confirming certain aspects of the infarction which cannot be ascertained by the latter method of staining. Pathological alterations associated with myocardial infarction at successive ages are explained and various methods of estimating the time of the infarction are discussed. Thus, gross and microscopical appearances of the acute, organizing and healed myocardial infarction are illustrated by photographs and the forensic applications of these morphological changes are discussed. Lastly, a rare case of an acute myocardial infarction associated with a heat stroke is presented and the medicolegal problems resulting from this case are discussed.