CHD is the single greatest cause of death in industrialized world occurring in both sexes, but presenting earlier in men. In developed countries it remains a significant diagnosis in 20-25% of the population. IHD is the epidemic menace of the mid-twentieth century. Before the age of 60 years an average healthy adult has got one in five chance of suffering from myocardial infarction and for dying the chance is one in fifteen. This monograph highlights the association of IHD with the ABO blood group in the local population of Pakistan.