Abstract: Objective: To investigate the value of endoscopic ultrasonography (EUS) in diagnosis of the ampullary carcinoma. Methods: Twenty-six patients with ampullary carcinoma were examined by EUS, and were compared with the results of US, HCT and MRI. Results: As compared with the postoperative pathological diagnosis, the overall accuracy of EUS in detecting the direct signs of ampullary carcinomas was 100%, only indirect signs of the disease were identified in majority of the cases using other methods. The EUS was significantly much more superior compared to the US (P<0.0001), HCT (P=0.0045) and MRI (P<0.0001) methods. Conclusion: The method of EUS is more accurate in detecting ampullary carcinoma compared to US, HCT and MRI, especially in direct detection of the ampullary tumor.