Data on the study of the genetics of ischemic heart disease by means of the classical methods (genealogical, population-statistical, and twin) are discussed. The results of a follow-up, conducted for many years, of the condition of close relatives of sick and healthy probands, who were found to be practically healthy during the first examination are discussed. Clinical biochemical examination of the relatives of sick probands is considered a necessary stage in the further clinical study of the genetic factors in ischemic heart disease. The most important problems in the study of the genetics of ischemic heart disease in the clinic are outlined.