Coronary artery fistula is a rare anatomic abnormality of the coronary arteries that affects 0.002% of the general population and represents 14% of all anomalies of coronary arteries. Its clinical relevance focuses mainly on the mechanism of the coronary steal phenomenon, causing myocardial functional ischemia, even in the absence of stenosis; therefore, angina and effort dyspnea are common symptoms. The suggested diagnostic approach is driven by patients' symptoms, and it consists of a number of instrumental examinations like ECG, treadmill test, echocardiography, computed tomography scan, cardiac magnetic resonance, and coronary angiography. If it is not an incidental finding, coronary angiography is required in view of optimal therapeutic planning. Small fistulae are usually asymptomatic, and prognosis is excellent if they are managed medically with clinical follow-up and echocardiography every 2 to 5 years. Large/giant, symptomatic fistulae, on the contrary, should undergo invasive closure, via either transcatheter approach or surgical ligation, whose results are equivalent at long-term follow-up. Antibiotic prophylaxis for prevention of bacterial endocarditis is recommended in all patients with coronary artery fistulae who undergo dental, gastrointestinal, or urological procedures. Life-long follow-up is always essential to ensure that the patient does not undergo progression of the disease or further cardiac complications.