Background: Neoadjuvant chemoradiotherapy is administered to patients with esophageal carcinoma with the belief that this will both downstage the tumor and improve survival. Endoscopic ultrasound (EUS) is currently the most accurate method of staging esophageal cancer for tumor (T) and lymph node (N) status. Because both EUS and neoadjuvant therapy for esophageal carcinoma are relatively new, there are few data examining the relationship between EUS stage and histological stage (the stage after resection) in patients receiving neoadjuvant therapy. Methods: To determine the effect of neoadjuvant chemoradiotherapy on T and N stage as determined by EUS, we retrospectively compared two groups of patients with esophageal cancer staged by EUS. One group (33 patients) underwent neoadjuvant therapy (Walsh protocol: 5-fluorouracil, cisplatin, and 4000 rads of external beam radiation) followed by resection. The second group (22 patients), a control group, underwent resection without neoadjuvant therapy. We then compared histological stage to determine if there was a downstaging in the patients receiving neoadjuvant therapy. Survival was evaluated as well. Results: EUS accurately predicted histologic stage. In the control group EUS overestimated T stage in 3 of 22 (13%), underestimated N stage in 2 of 22 (9%), and overestimated N stage in 2 of 22 (9%) of patients. Preoperative radiochemotherapy downstaged (preoperative EUS stage versus pathologic specimen) 12 of 33 (36%) of patients whereas only 1 of 22 (5%) of patients in the control group was downstaged. Complete response (no tumor found in the surgical specimen) was observed in 5 of 33 (15%) of patients receiving radiochemotherapy. Survival was prolonged significantly in patients receiving radiochemotherapy: 20.6 months versus 9.6 months for those (stage II or III) patients not receiving radiochemotherapy ( P <0.01). Operative time, operative blood loss, and length of stay were not significantly different between groups. Perioperative mortality was higher in the radiochemotherapy group (13%) compared with the no radiochemotherapy group (5%) but did not achieve statistical significance. Conclusions: EUS accurately stages esophageal carcinoma. Neoadjuvant radiochemotherapy downstages esophageal carcinoma for T and N status. In our nonrandomized study, neoadjuvant therapy conferred a significant survival advantage. Operative risk appears to be increased in patients receiving neoadjuvant radiochemotherapy prior to esophagectomy.