PURPOSE: Peritoneal recurrence has been reported to be the most common form of recurrence of gastric cancer. Peritoneal recurrence can generally be suggested by several types of image studies and also if there is evidence of ascites or Bloomer's rectal shelf. It can be confirmed by explorative laparotomy, but diagnostic laparoscopy is a good alternative method and laparoscopic surgery has also been widely used. We reviewed and analyzed the ability of diagnostic laparoscopy to detect peritoneal recurrence or carcinomatosis, and especially for gastric cancer. MATERIALS AND METHODS: We performed a retrospective review the 45 gastric cancer patients who were operated via diagnostic laparoscopy between 2004. 2. and 2009. 3. We analyzed the perioperative clinical characteristics and the accuracy of the diagnostic methods. RESULTS: The study groups included 14 patients who had confirmed gastric cancer, but they suspected to have carcinomatosis, and 31 patients who had previously underwent gastric resection, but they suspected to have recurrence. The mean operation time was 44.1+/-6.9 minutes and the mean postoperative hospital stay was 2.7+/-.8 days. There was one case of operation-related complication and no postoperative mortality occurred. The sensitivities for detecting peritoneal recurrence or carcinomatosis were 92.1% for diagnostic laparoscopy, 29.7% for detecting ascites and rectal shelf on the physical examination, 86.5% for abdominal computed tomography, 69.2% for PET CT and 18.8% for CEA. CONCLUSION: Diagnostic laparoscopy does not require a long operation time or a long hospital stay, and it showed a low complication rate in our study. It has high sensitivity for detecting peritoneal recurrence of gastric cancer. It can be an alternative diagnostic confirmative method and it is useful for deciding on further treatment.