Presence of persistent left superior vena cava(PLSVC) is considered to be one of the most frequently encountered anomalies of the systemic venous return. The incidence of PLSVC is reported to be 0.3% to 0.5% in the general population, and in 3% to 10% of patients with congenital heart disease. The presence of PLSVC draining into the coronary sinus is of no hemodynamic significance. However, it is important to recognize this condition, as it can have important clinical implications. The diagnosis can be established by two demensional echocardiography. It should be suspected by the presence of dilated coronary sinus, and confirmed by contrast echocardiography. A 61-year-old man with chronic atrial fibrillation was diagnosed as PLSVC by contrast transthoracic echocardiography(TTE) using agitated saline. Contrast TTE allowed visualization of the time sequence of the echo-contrast within the right atrium first following injection of right antecubital vein. Following injection of left antecubital vein, opacification of the dilated coronary sinus first and then the right atrium was seen.