Surgical Site Infection (SSI) is one of the most serious post-operative complications and therefore its prevention is extremely important. SSI risk factors were evaluated in 337 cardiac valvular surgical cases without concomitant CABG or the thoracic great vessels interventions which had been performed in our center between January 2008 and December 2010. The Center for Disease Control and Prevention definition of SSI was used for case determination. The SSI incidence was 4.7% (16 cases). Univariate analysis found statistical significance in history of cardiac surgery, LVEF, surgical procedures, operative time and morning glucose level on post-operative days (POD) 1 and 2. POD 1 morning glucose level higher than 150 mg/dl (odds ratio 4.2 ; 95% confidence interval 1.3-13.7) and operative time (odds ratio 2.0 ; 95% CI 1.2-3.5) were identified as independent factors by multiple logistic regression. According to SSI rate comparison by glucose-level, the incidence was higher when POD 2 morning glucose level exceeded 150 mg/dl as in the case of POD 1 (p<0.02). Longer operative time represented higher SSI rates in interquartile range-based comparison. This study suggested values of reducing surgical time and controlling POD 1 morning glucose level within 150 mg/dl.