Background: Reoperation of cardiac surgery via median sternotomy can be associated with significant complications. Thoracotomy is expected to reduce the risk of reoperation and to enhance the surgical outcomes. We retrospectively analyzed two operative approaches (thoracotomy vs. sternotomy) in cardiac reoperation. Materials and Methods: From September 2007 to December 2010, 35 patients who required reoperation of the mitral valvular disease following previous median sternotomy were included. Average age of patients was $45.8{pm}15.4$ years (range, 14 to 76 years) and male-to-female was 23:12. Interval period between primary operation and reoperation was $135.8{pm}105.6$ months (range, 3.3 to 384.9 months). Results: Comparative analysis was done dividing the patient group into two groups that are thoracotomy group (22 patients) and sternotomy group (13 patients). Thoracotomy group was significantly lower in operative time ($415.2{pm}90.3$ vs. $497.5{pm}148.0$, p<0.05), bleeding control time ($108.0{pm}29.5$ vs. $146.4{pm}66.8$, p<0.05) and chest tube drainage ($287.5{pm}211.5mL$ vs. $557.3{pm}365.5mL$, p<0.05) compared to sternotomy group. Conclusion: The thoracotomy approach is superior to sternotomy in some variables, and it is considered as a valid alternative to repeat median sternotomy in patients who underwent a previous median sternotomy.