PURPOSE: This study was designed to evaluate the bacteriological characteristics and antibiotics sensitivity in acute appendicitis. METHODS: The microbiologic culture and antibiotics sensitivity tests were done on 165 patients who underwent laparoscopic appendectomy under the diagnosis of acute appendicitis. The postoperative complications were also checked. The microbiologic and clinical results were compared between perforated and non-perforated groups. RESULTS: The most common organism cultured from the periappendiceal fluid was Escherichia coli (51.2%), followed by Enterobacter (16.2%) and Pseudomonas (8.9%). In the antibiotics sensitivity test, ciprofloxacin and levofloxacin were highly susceptible. Ceftriaxone and cefotaxime were also highly susceptible. Piperacillin/tazobactam, imipenem and meropenem were very highly susceptible. The complication rate of perforated appendicitis group (17.9%) was higher than that of the non-perforated appendicitis group (7.1%) (P<0.001). A surgical drain was used more frequently in perforated group (23% vs 84.6%, P<0.001). The mean in-patient days were longer in the perforated group (5.7 vs 7.2 days, P<0.001). In the patients with infectious wound complication, antibiotic resistance was more prominent in the non-perforated group than in the perforated group. CONCLUSION: In the perforated appendicitis group, more precise and careful procedure was required. In the non-perforated appendicitis group, more prudent use of the available antibiotics to conserve valuable therapeutic resources and improved infection control to limit the spread of resistant organisms was required.