Objective To analyze symptoms, associated anomalies, diagnostic approach, and surgical procedures in patients with unroofed coronary sinus syndrome (UCSS), a rare congenital disorder. Methods The clinical, echocardiographic, operative, and followup data on 44 patients with unroofed coronary sinus syndrome (typeⅠin 15，typeⅡin 9，type Ⅲ in 5 and type Ⅳ in 15) between May 1998 and January 2008 were reviewed retrospectively. The initial diagnosis of unroofed coronary sinus syndrome was made by echocardiography in 12 patients, by the surgeon at repair of other congenital cardiac anomalies in 32 patients. The patients underwent cardiovascular surgery at Fu Wai hospital. Left superior vena cava(LSVC) directly drains into the left atrium (LA) were found in 15 cases, LSVC was ligated in 1 case, the intracardiac tunnel to drain LSVC to right atrium (RA) were reconstructed in 14 cases. The associated cardiac lesions were corrected concomitantly. Results There were 3 hospital deaths. One patient died of low cardiac output syndrome and 2 patients died of pulmonary infection. One case was applied diaphragm plication because of right diaphragm paralysis after the heart operation and the hospital stay was 70 days.The other 40 cases had good surgical result. The average time of extubation was 11.7±12.1 h and hospital stay was 8.1±2.8 d. In the 32 cases, who have been followed up from 4 months to 10 years, there was no death and severe complications. Conclusion Unroofed coronary sinus syndromes are often missed in the preoperative evaluation of congenitally malformed hearts. When associated with LSVC, unroofed coronary sinus syndrome should be considered as a possible additional finding.We performed different surgical approaches to deal with the different kinds of LSVC with a good result.