3 patients with different clinical and electrocardiographic manifestations of coronary artery spasm are discussed. All 3 patients had anginal attacks at rest. In addition, 2 of these patients, who did not have significant preexisting narrowing of their coronary arteries, also had anginal pain related to exercise. During pain, 1 patient showed ST-segment elevation, the other ST-segment depression, while the third showed ST-segment depression shortly followed by ST-elevation on the electrocardiogram. At coronary angiography, spontaneous or induced spasm of one of the major coronary arteries could be demonstrated in all 3 patients. In 2 cases, sublingual nitroglycerin failed to completely relieve the spasm. This raises the question whether a residual stenosis after NTG conclusively proves a fixed organic narrowing. It is concluded that the clinical spectrum of spasm of the coronary arteries is wider than was originally reported by Prinzmetal and coworkers. Clinical and electrocardiographic manifestations are probably dependent on the site and severity of the spasm, which may cause different degrees of myocardial ischemia.