The authors report 36 cases of spontaneous angina occurring in the absence (group A) or presence (group B) of a myocardial infarct (MI), either recent or old, and accompanied, during the attacks, by transient ST elevation (T ST E) and normal enzyme levels. Group A (16 cases) was characterised by : a) the severity of the prognosis with the development of rhythm disturbances during the attacks in 10 out of 16 cases, and of a MI and/or sudden death in 4 of the 6 cases treated medically; b) the presence, in 12 of the 14 cases explored of surgical stenosis of a major coronary trunck. The simple association of attacks of spontaneous angina and T ST E is in general sufficient to define severe angina, regardless of the height of the elevation, and for which a surgical indication (95 p. cent of our cases) with the same problems as those posed by Prinzmetal angina strictly defined on a series of clinical and electrocardiographic criteria. Group B (20 cases) :a) differed from group A by the incidence of cardiac failure (15 out of 20 cases), the widespread nature and degree of the anatomical lesions, not usually amenable to by-pass; b) the severe prognosis, reflected in 6 of the 17 cases treated medically by extension of the MI and/or sudden death, did not differ fundamentally from that of any subsequent relapse, regardless of its electrocardiographic signs. In these cases, the T ST E related to the presence of the MI does not have the same significance as in Prinzmetal angina, and progressive relapses of MI should no longer be classified in this group on the pretext that they are accompanied by T ST E.