The coronary slow flow phenomenon (CSFP) is an angiographic finding characterized by delayed opacification of the epicardial coronary arteries in the absence of significant stenosis, spasm, dissection or thrombus. Although this poorly understood phenomenon received little attention, patients with CSFP at coronary angiography often suffer from recurrent episodes of chest pain, sometimes occurring during an acute coronary syndrome. We describe 3 cases of patients with CSFP who complained of recurrent chest pain; in one of them an episode of chest pain was so severe as to bring the patient to the emergency department. Indeed, in all our 3 cases myocardial ischemia was evaluated on the basis of a positive myocardial scintigraphy result. In conclusion, it is suggested that CSFP may be an acute and recurrent perturbation of microvascular function with an often severe impairment of quality of life. Myocardial perfusion scintigraphy might help for an accurate assessment of myocardial ischemia in such patients.