Objective To evaluate the accuracy of preoperative 64 multidetector spiral computed tomography (MDCT) in the diagnosis of stage Ⅳ gastric cancer. Methods The data of patients with stage Ⅳ gastric cancer between July 2007 and April 2008 were collected. Twenty-nine patients underwent preoperative 64 MDCT were retrospectively analyzed. All computed tomography scans were prospectly analyzed by 2 abdominal radiologists separately. Pathological tumor stage was based on TNM stage according to the revised Japanese Classification of Gastric Carcinoma from the Japanese Gastric Cancer Association. All CT results were compared with clinical, surgical and histopathologic results. Results The 65.2% (15/23), 47.8% (11/23) and 70.8% (17/24) of the stage Ⅳ patients were accurately predicted of T, N and M stage, respectively. Moreover, 58.6% (17/29) of the stage Ⅳ patients were accurately predicted of TNM stage. But 6/9 cases with peritoneal metastases were not detected by preoperative 64 MDCT. Conclusion The 64 MDCT is a promising technique for detection and preoperative staging of stage Ⅳ gastric cancer. It was difficult to detect peritoneal metastases, but it may not increase the rate of exploratory laparotomy.