Abstract: Objective: A study was performed to evaluate the diagnostic value for positron emission tomography （PET） using fluorodeoxyglucose （FDG） in patients with primary or recurrent gastric cancer correlated with computed-tomography. Methods: 28 patients were included in the study. All patients had a PET scan. Preoperative staging of gastric cancer with CT were performed in 23 patients. These results were compared with the histopathological staging to evaluate the accuracy and usefulness of PET preoperation staging of patients with gastric cancer. Results: The accuracy in detecting primary tumor （T） by PET and CT was 92.9% and 82.6% respectively. For N the PET scan was accurate in 87.5% compared with CT in 61.9%. PET identified 8/8 patients with distant metastases and CT 4/7. Conclusion: PET scanning is a sensitive method for detecting lymph node and metastatic leision in patients with primary or recurrent gastric carcinoma compared with CT. PET appeared to be better in assessing recurrent tumour than CT.