The ability of preoperative CT to assess resectability and to stage carcinoma of the esophagus and gastroesophageal junction was studied in 71 patients who underwent transhiatal esophagectomy. Patients with preoperatively proven distant metastases who did not have surgery were not included in the present study. At surgery the tumor invaded adjacent mediastinal or abdominal structures in 18 patients (prevalence 25%), but was nonresectable in only 7 of these 18 patients (39%). Invasions of the tracheobronchial tree, the aorta, and the diaphragm were correctly detected on CT in 5 of 6, 1 of 2, and 2 of 10 patients. There were four false-positive results on CT; tracheobronchial invasion and pericardial invasion were incorrectly predicted in one and three patients, respectively. Invasion of adjacent structures was correctly assessed on CT in 58 (82%) patients and the depth of tumor invasion was correctly determined in 49 (69%) patients. Computed tomography correctly staged 57% of patients according to the classification of the American Joint Committee on Cancer. Understaging (31%) occurred more often than overstaging (11%). In the present study, computed tomography was not effective in assessing non-resectability by diagnosing invasion because of the relatively low prevalence of invasion of adjacent structures and the fact that invasion was often not associated with nonresectability. In assessing invasion itself, CT was accurate in diagnosing tracheobronchial involvement, but was limited in diagnosing invasion of other adjacent structures. In assessing stage grouping, CT was limited in detecting either diaphragmatic invasion or lymph node involvement.