Patients with epithelial or mucosal carcinoma of the esophagus are considered to have a much better prognosis than those with submucosal carcinoma, although both lesions are classified as superficial carcinomas of the esophagus. With this in mind, we evaluated the usefulness of endoscopic ultrasonography for pre-operatively distinguishing either epithelial or mucosal carcinoma from submucosal carcinoma by comparing the results of endoscopic ultrasonography with the histological findings established in resected specimens. Between 1987 and 1991, 26 patients with no pre-operative treatment were confirmed histologically to have epithelial (2 cases), mucosal (11 cases) or submucosal (13 cases) carcinomas of the esophagus. In 13 patients with epithelial or mucosal carcinoma, 10 were correctly diagnosed with endoscopic ultrasonography (76.9%), while the remaining 3 were overdiagnosed as being submucosal. In 13 patients with submucosal carcinoma, 12 were correctly diagnosed by endoscopic ultrasonography (92.3%), although another case was overestimated. Including one patient with an advanced carcinoma who was underdiagnosed by endoscopic ultrasonography as having a submucosal lesion, the overall accuracy of endoscopic ultrasonography was 81.5% for diagnosing the depth of invasion of a superficial esophageal carcinoma. The above results show that endoscopic ultrasonography can provide surgeons with important information in the pre-operative assessment of a superficial esophageal carcinoma.