Introduction: This study was aimed to evaluate the utility and shortcomings of EUS (endoscopic ultrasound) in TNM staging of gastric cancer and its influence on treatment. Methods: The series included 126 gastric cancer patients underwent EUS from July 1997 to June 2003 at National University Hospital, Singapore. 109 patients were included in the final analysis. There were 65 male and 44 female patients with age range 29 to 97 years(mean 63.13). Results: EUS staging for primary: Specimen histology was available for 102/109 patients operated. The accuracy for T1, T2, T3 and T4 was 79%, 73.9%, 85.7% and 72.7% respectively (overall accuracy = 80.4%). EUS staging for Nodes The sensitivity of EUS for detecting nodal disease was 74.2% for N0, 78% for N1, 53.8% for N2 and 50% for N3 respectively. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for N staging by EUS were 82.8%, 74.2%, 85.4%, 70.2%, and 79.8%, respectively . Radical gastrectomy was proposed in 95 patients based on the staging with EUS and CT scan and 87 patients underwent the same (91.6%). Preoperative staging accurately predicted the operative strategy in 89% of the patients. Performing a logistic regression analysis for the correct staging of T stage using EUS and adjusting for tumor location (middle part / distal third / whole stomach versus Proximal/Cardio-esophageal) (p = 0.873), operator (p = 0.546)and subject's sequence (Initial 50 versus last 50 cases)(p = 0.06), there was no significant predictor for accuracy. Conclusion EUS is the most accurate and reliable method for preoperative staging of gastric carcinomas and mandatory if tailored therapeutic approach is planned according to stage. Introduction: This study was aimed to evaluate the utility and shortcomings of EUS (endoscopic ultrasound) in TNM staging of gastric cancer and its influence on treatment. Methods: The series included 126 gastric cancer patients underwent EUS from July 1997 to June 2003 at National University Hospital, Singapore. 109 patients were included in the final analysis. There were 65 male and 44 female patients with age range 29 to 97 years(mean 63.13). Results: EUS staging for primary: Specimen histology was available for 102/109 patients operated. The accuracy for T1, T2, T3 and T4 was 79%, 73.9%, 85.7% and 72.7% respectively (overall accuracy = 80.4%). EUS staging for Nodes The sensitivity of EUS for detecting nodal disease was 74.2% for N0, 78% for N1, 53.8% for N2 and 50% for N3 respectively. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for N staging by EUS were 82.8%, 74.2%, 85.4%, 70.2%, and 79.8%, respectively . Radical gastrectomy was proposed in 95 patients based on the staging with EUS and CT scan and 87 patients underwent the same (91.6%). Preoperative staging accurately predicted the operative strategy in 89% of the patients. Performing a logistic regression analysis for the correct staging of T stage using EUS and adjusting for tumor location (middle part / distal third / whole stomach versus Proximal/Cardio-esophageal) (p = 0.873), operator (p = 0.546)and subject's sequence (Initial 50 versus last 50 cases)(p = 0.06), there was no significant predictor for accuracy. Conclusion EUS is the most accurate and reliable method for preoperative staging of gastric carcinomas and mandatory if tailored therapeutic approach is planned according to stage.