Three groups, with one hundred subjects in each, were formed randomly. The first group consisted of members from urban area, second of country population, both having arterial hypertension, while in the third group were subjects without arterial hypertension. Analysis was made in order to find the relation between diastolic component of blood pressure, the level of hypertension and the period of its duration as well as the difference of these parametres between the urban and country population. The incidence of the ischaemic heart disease was considered in all three tested groups. The investigation showed the absence of considerable statistical difference in the level of hypertension and the period of its duration between the urban and country population. Ischaemic heart disease is equally presented in all three groups. It appears more frequently in men than in women, but the difference is not statistically important. Analysing the relation between frequency of appearance of the ischaemic heart disease and the level of hypertension it was found that it appears more frequently in subjects with slight arterial hypertension, with a high level of correlation.