The purpose of the investigation was to study the possibilities of involving the population at large in mass screening procedures, the possible classification of the population with regard the degree of risk of ischaemic heart disease, and the potentials of its preventive therapy. The examined contingent was classified with due regard to some risk factors (arterialy hypertension, hypercholesterolemia, imparied glucose tolerance) and pathological states. The final grouping of the contingent was as follows: the group of "normal" was comprised by 53.4% of the examined, the "intermediate"-18.6%, the "pathological"-28%. The "intermediate" group comprised 350 persons selected for preventive therapy by a double blind method. Surveillance of 10% of those in the "normal" group and the whole "pathological" group was arranged.