Patients who underwent surgical resection of an advanced colorectal cancer during the period from June 1982 to July 2001 were examined for evidence of no anastomotic recurrence or recurrent lesions through combination of endoscopic ultrasonography (EUS) with endoscopy. Included in this study were 11 patients with recurrence and 36 patients without recurrence, 47 patients in all. Endoscopy revealed stenosis in 81.8% of patients with ana anastomotic recurrence, erosion including cancer exposure in 81.8% and submucosal tumor-like elevation in 45.5%. In the group of patients without recurrence it revealed stenosis in 13.9% of patients, erosion in 22.2%, and a scar-like change in 77.8%. There was a significant difference between the two groups in each change. EUS, on the other hand, revealed localized hypertrophy of the region extending from the submucosa to the mp due to edema early in the postoperative course. The rate of definitive diagnosis with EUS was 100%, compared to 90.1% for endoscopy. The results of this study indicate that EUS is helpful in detecting anastomotic recurrence of colorectal cancer.