PURPOSE: Prophylactic antibiotics have been used in nonperforated appendicitis for preventing infection after an appendectomy. However, the duration of antibiotic administration for surgical prophylaxis in Korea has been noted to be longer than those recommended in other countries. PURPOSE: The objective of this study was to identify the appropriate duration of prophylactic antibiotic therapy in nonperforated appendicitis by comparing the wound infection rates of two different antibiotic regimens, 24 hours of cephalosporin (cefoxitin) alone and 72 hours of cephalosporin (cefoxitin) with aminoglycoside (sissomicin). METHODS: One hundred thirty-four (134) patients of nonperforated appendicitis were enrolled in this prospective, randomized, open trial and were assigned to one of two antibiotic regimens: 1) cefoxitin 1 g every 8 hours given intravenously for 24 hours and 2) cefoxitin 1 g every 8 hours given intravenously plus sissomicin 75 mg every 12 hours given intramuscularly for 72 hours. First doses were given just prior to the induction of anesthesia. RESULTS: Postoperative wound infections were detected in 3 cases (4.5%) of the 72-hour-treated group (n=66) whereas none occurred in the 24-hour-treated group (n=68). However, the difference in the rates of wound infections between the two groups was not statistically significant. Cost analysis identified a saving of 43,470 won per patient in the 24-hour-treated group. CONCLUSION: In nonperforated appendicitis cefoxitin administration alone for 24 hours is sufficient as a surgical prophylaxis.