To study the role of the vasospastic factor in the etiology of CHD pain forms a total of 326 patients were examined using coronary angiography, of them a test with i. v. administration of ergometrine was made to 117. An analysis of the peculiarities in the CHD course showed that angina destabilization usually associated with the addition of a dynamic component, could occur in a different duration of disease. The first clinical signs of CHD in more than half of the cases in a stable and unstable course of angina developed in the marked obstructive involvement of the coronary bed. Obvious vasospastic reactions in the ergometrine test were more frequently noted with recently developed unstable angina however they could occur in a different period of disease. The data obtained indicated that in most cases two mechanisms were involved in the development of angina: fixed coronary obstruction as a morphological basis of coronary insufficiency and spasm of the coronary arteries which could be a leading factor in a number of patients or determine angina instability.