Records of 487 patients in long-term follow-up after Ro resection of colorectal carcinomas between January 1, 1980 and December 31, 1989 were analyzed. Every patient underwent regular examinations according to a defined schedule after curative resection of colorectal carcinoma. The date of evaluation was June 31, 1991. During a median observation time of 48 months (range, 15-132 months), tumor recurrence was observed in 149 patients (30.6 percent), with 56.4 percent of these suffering from tumor-associated symptoms. As the primary manifestation of tumor recurrence, only distant metastases (DM) were found in 76 patients (51 percent), only local recurrence (LR) in 46 patients (30.9 percent), and both DM and LR in 27 patients (18.1 percent). Patients with rectal carcinoma developed LR more frequently (P < 0.05) (19.5 percent) than patients with colon carcinoma (11.8 percent). The probability of developing distant metastases was not different (P < 0.05) for colon or rectal carcinoma but depended on primary tumor stage (P < 0.05). Only 36 patients (24.2 percent) with recurrence could undergo further curative resection. Fifty patients (33.5 percent) were given palliative therapy, and 63 patients (42.3 percent) were given no oncologic treatment. Only 9 of the 36 patients (6 percent of all recurrence patients) undergoing Ro resection were free of tumor for more than two years. In no case was a third Ro resection possible. The survival time of these patients was increased significantly after Ro resection of tumor recurrence (P = 0.03). Our study suggests that only a very few patients may live longer as a result of regular follow-up programs after curative resection for colorectal carcinoma.