Staging of esophageal squamous cell carcinoma is a prerequisite to assessing prognosis and deciding on appropriate treatment. Endoscopy provides one means of predicting the extent of tumor growth. Using the classification of the Japanese Society for Esophageal Diseases, which differentiates superficial (type 0) from more advanced stages of esophageal carcinoma, we studied 273 patients with squamous cell cancer of the esophagus. Histopathologic examination of resected specimens (N = 81) or endosonography (N = 128) served to correlate the endoscopically defined categories with the otherwise determined T stages. Not classifiable by endoscopy were 64 patients (23.4%), 42 of whom were pre-treated by means of chemo- or radiation therapy. In the remaining 209 patients, it could be shown that endoscopic assessment was both sensitive (78%) and specific (93%) in predicting the local extent of tumor (overall accuracy, 89%). Detailed analysis showed good sensitivity for stage 0 (83%) which corresponds to T-1 carcinoma and for stages 3 and 4 (82% and 83%) which represent T-3 and T-4 tumors. Only in endoscopic stages 1 and 2 was the concordance with the T stage (T-2) weaker, with a sensitivity of 52%. We conclude that prediction of local tumor extent by endoscopic observation is a generally reliable means of pre-operative staging esophageal cancer.