Purpose: To identify risk factors for surgical site infections in patients undergoing general surgery, to analyze the prolonged hospital stay and extra cost for antibiotics, and to provide basic data for control of surgical site infections. Method: Surgical site infection was defined using the definition of the CDC and the data were analyzed by $x^2$-test and unpaired t-test. Results: The prevalence of surgical site infections was 9.7%, and it was related to wound class, duration of operation, number of operations, whether the operation was an emergency, trauma, drains, preoperative stays, presence of remote infection during operative period, and previous history of recent surgery. The mean duration for post-operative stay when a surgical site infection occurred was 9.5 days and in 56.9 % of the patients the surgical site infection appeared 7 days after the operation. Post-operative stays for infected patients were 20.3 days longer than that of uninfected patients. The mean cost of antibiotics for infected patients was higher than that for uninfected patients by 561,067 won per person. Conclusion: Surgical site infection results in an increased length of stay and extra-cost, thus, hospitals need to create strategies to reduce nosocomial infections through effective infection surveillance and by considering factors related to surgical site infections.