The aim of this study was to assess the accuracy and limitation of Endoscopic ultrasonography (EUS) in the preoperative evaluation of the cardiac cancer (cancer in the area less than 2 cm from the esophago-gastric junction). EUS was preoperatively performed in 20 patients with cardiac cancer. These cases were visualized by the water immersion method and balloon contact method. The results were correlated with the histology of resected specimens. EUS was accurate in assessing the depth of tumor infiltration. Over all accuracy of EUS for cardiac cancer was 90%. Recognition of ultrasonographic patterns had enabled us to judge the mode of tumor infiltration whether expansive or infiltrative. Microscopical spread over 5 mm to the esophagus of the cardiac cancer could be detected by EUS. EUS was accurate in diagnosing thoracic lymph nodes (No. 110, 111, 112) metastasis of the cardiac cancer (accuracy 86%). EUS was valuable in the clinical diagnosis of the cardiac cancer.