A variant form of angina pectoris was observed in 23 patients. The clinical features, diagnosis, treatment, pathological physiology, and chemical changes are summarized. Chest pain developed when the patients were at rest or relatively inactive. Electrocardiograms, recorded during this type of anginal pain, showed an elevation of the S-T segment which disappeared when the pain stopped. The electrocardiogram may, therefore, show findings opposite to those of ordinary angina pectoris. In mild attacks the electrocardiogram may show spurious improvement. Sufficient diagnostic features are pointed out to allow for clinical diagnosis of typical cases, and two case histories illustrate the course and treatment of this condition.