We experienced one case of the calcified giant thrombosis in the enlarged right atrium and coronary sinus with markedly dilated persistent left superior vena cava and absent right superior vena cava in 29year old female patient. We supposed that the dilatation of persistent left superior vena cava was due to poststenotic dilatation secondary to obstruction on orifice of coronary sinus by thrombosis. The giant thrombosis in the right atrium and coronary sinus was successfully resected. She had improvement on preoperative chest discomfort but, the moderate hepatomegaly was developed and then she was discharged with incompletely recovered state due to economical poverty on postoperative 6th weeks. The continuous follow-up and study are indeed necessary for further evaluation of pathology and etiology.