The most common complication after liver transplantation (LT) is bacterial infection. The incidence of surgical site infections (SSIs) after LT was variable from 8.8%~37%. However, there has been no confirmed guideline in use of prophylactic antibiotics after LT. Ampicillin/sulbactam has been used as main prophylactic antibiotics after LT in Seoul National University Hospital (SNUH) according to the center protocol. The purpose of this study was to determine the incidence and risk factors for SSI after LT and to evaluate the appropriateness of prophylactic antibiotics. A total of 211 patients who underwent LT between July 2008 and June 2010 at SUNH were included. During study period, ampicillin/sulbactam was selected as prophylactic antibiotics in 140 patients (66.4%). A total of 43 patients (20.4%) developed infections and the incidence of SSI was noted in 28 patients (13.2%); 10.0% in ampicillin/sulbactam group and 19.4% in other antibiotics (p=0.049). The most common pathogen of SSI was MRSA (13 episodes, 49.4%). In multivariate analysis, choledochojejunostomy (OR: 7.0; 95% CI, 2.4-20.0) and lower serum albumin (OR: 3.7; 95% CI, 1.1-12.9) were found to be risk factors of SSIs. In conclusion, the incidence of SSIs after LT in this population was similar to those in other studies. Therefore, the prophylactic antibiotics protocol in LT at SNUH seems to be appropriate.