PURPOSE: The use of prophylactic antibiotics is the current standard of care after elective colorectal surgery. The aim of this study was to compare the efficacy of antibiotic prophylaxis with dual antibiotic therapy and triple antibiotic therapy after elective colorectal surgery. METHODS: We studied consecutive patients underwent elective colorectal surgery from January to June, 2007. Patients of triple-therapy group were administered second cephalosporin, metronidazole, and aminoglycoside for early 3 mo and dual-therapy group were administered second cephalosporin and metronidazole for next 3 mo. The prophylactic antibiotics were administered 2-3 doses for 24 hr after surgery. The surgery for diverticulitis, inflammatory bowel disease, and colon obstruction were excluded. Wound conditions were checked on alternate days during the hospital stay and follow up at least for 30 days after discharge. RESULTS: Over 6 mo, 110 patients were enrolled (59 dual-therapy group, 51 triple-therapy group). In two group, sex, age, American Society of Anesthesiology score, body mass index, combined diseases, and location of disease were similar. Wound infection rate were 1.7% in dual-therapy group and 2.0% in triple-therapy group (P=1.0). Anastomotic leakage rate were 5.1% in dual-therapy group and 2.0% in triple-therapy group (P=0.622). CONCLUSION: The addition of aminoglycoside to dual antibiotic therapy, second cephalosporin-metronidazole showed on advantage in prevention of postoperative wound complications. Further studies are required to establish appropriate guideline of antibiotic prophylaxis after elective colorectal surgery.