OBJECTIVE The average rate of surgical site infections (SSIs) for laparoscopic cholecystectomy (LC) has been reported in the literature to be between 0.4% and 6.3%. Also, these recent reviews have concluded that a prophylactic antibiotics for elective LCs in low-risk patients is not useful, but there were no results in high-risk patients. METHODS The aim of this study was to investigate the role of a single dose of first-generation cephalosporin as a prophylactic antibiotic for patients undergoing elective LC, regardless of patient risk. This randomized clinical trial was conducted from October 2013 to December 2014 by single surgeon at our hospital. Patients were randomized into two groups by following method. Odd-numbered patients (group A) received 1-g cefazolin intravenously within 30 minutes before incision, whereas even-numbered patients (group B) received normal saline intravenously instead of prophylactic antibiotics, with the aim of including 100 patients in each group. SSIs were recorded and compared between the groups. RESULTS There were no differences in preoperative demographics and postoperative findings between the groups. There were no superficial and deep SSIs in either group, 9 cases of superficial seromas developed (4.5%) in the cohort: 4 in group A (4%) and 5 in group B (5%). There were no significant associations between SSIs and the use of prophylactic antibiotics in either group. Additionally, the high-risk group did not show a significantly increased rate of SSIs. CONCLUSIONS Based on our study, prophylactic antibiotics are not necessary in elective LC, regardless of patient risk.