The paper gives the results of survey of 99 families of patients with prior myocardial infarction. There was a high coronary heart disease (CHD) affliction among the blood relatives of probands and its clear-cut relationship to the specific features of their family history. The patients with prior myocardial infarction and their blood relatives showed profound changes in coagulative and anticoagulative factors, which indicate their tendency to hypercoagulation. The specific features of family history, the pattern of changes in hemostatic parameters in blood and non-blood relatives, and evidence for the genetic determination of the hemostatic parameter activity suggest that the blood coagulative system is an important component for hereditary predisposition to CHD. An association of some hemostatic parameters was examined with CHD. The paper provides strong evidence for the fact that it is expedient to measure antithrombin III activity as a marker of genetic predisposition to CHD while surveying a group of individuals who have a family history of CHD.