We used endoscopic ultrasonography (EUS) to clinically stage eight patients with adenocarcinoma of the esophagus and to monitor their disease after subsequent courses of experimental preoperative chemotherapy. Stage of disease (TNM), tumor area, and tumor width were determined at each session. These results were then compared with barium esophagram and histopathology from resection specimens. EUS provided a consistent interpretation of the stage of disease and accurately predicted histopathologic findings. Measurement of tumor area and maximal width did not reliably correlate with the response to chemotherapy as assessed by barium esophagram. Although this technique seems promising, it cannot yet be recommended as a means of predicting response to chemotherapy.