To investigate whether endoscopic ultrasonography could improve the preoperative staging of esophageal carcinoma we prospectively studied 56 tumors in 51 patients between March 1987 an March 1988. The results for assessing local and regional extension and preoperative staging were compared with those of computed tomography, surgery, and pathological findings. When the procedure was complete (n = 25) the accuracy of parietal spread assessment was 85.7 percent; sensitivity for nodal involvement was 83.3 percent versus 50 percent for computed tomography with an accuracy of 97.6 percent versus 96.4 percent; the discrimination between superficial and advanced cancer was 100 percent; the accuracy for preoperative staging using the Japanese classification was 84 percent. When the procedure was not complete (stenosis), endoscopic ultrasonography was complementary to computed tomography: local invasion of anatomical structures (n = 16) was better assessed by combined endoscopic ultrasonography and computed tomography (n = 11) than by endoscopic ultrasonography (n = 8) or computed tomography (n = 6) alone. We conclude that endoscopic ultrasonography is the best procedure for staging esophageal carcinoma without stenosis; further miniaturization of the transducer is necessary to improve results in the case of narrow stenosis.