Spinal cord stimulation (SCS) has been demonstrated to cause clinical improvement in patients with refractory angina pectoris in the number of anginal episodes, in nitroglycerin consumption, in maximal exercise time, in exercise time until angina, in the number of episodes of myocardial ischemia, in the duration of episodes of myocardial ischemia, and in ischemic ST-segment depression at a comparable workload. Double-blind, randomized, placebo-controlled studies have not been performed with SCS. The clinical improvement from SCS occurred despite no improvement in measured regional myocardial blood flow during exercise or in myocardial oxygen consumption as assessed by the heart rate times systolic pressure product at maximal exercise. The mechanisms of clinical improvement by SCS are unclear. SCS must be considered experimental at this time, and it remains a potential therapeutic option for the treatment of refractory angina pectoris in patients unable to have coronary revascularization or at very high risk for coronary revascularization.