In connection with the fact that lesions of the coronary artery can be approached only by coronarography, the possibilities of coronarography are discussed. The problems arising are, 1. the relationship between prognosis and the degree to which the coronaries are affected; 2. how to follow the degenerative lesion from the first event up to complete obstruction; 3. the relationship between coronarographic finding and clinical symptoms; and 4. why is it essential to be acquainted with the changed conditions of coronary circulation. A coronarographic finding taking into consideration the above points will play an important role when it has to be decided who should be subjected and to what type of operation improving the coronary circulation.