Ischemic chest pain syndromes and myocardial infarction occurred within minutes to hours of cocaine use in nine persons ages 23 to 39 years. Five developed symptoms after taking cocaine intranasally; three, after intravenous use; and one, after smoking cocaine. Four were habitual users and five were recreational users; eight also smoked cigarettes heavily. Ischemic syndromes recurred in five who continued to use cocaine. Coronary arteriography showed an abnormal infarct-related vessel (more than 50% stenosis, total occlusion, or intraluminal thrombus) in seven patients. The noninfarct vessels were normal in eight patients. The left anterior descending coronary artery and the anteroapical left-ventricular wall were involved in all patients. After three patients had successful thrombolysis of the obstructed infarct-related vessel, angiography showed a normal underlying vessel.