A group of 95 patients, treated with irradiation for relapse after radical surgery as only initial treatment modality for a rectal carcinoma was studied. The term locoregional relapse relates to evidence of tumor recurrent in the pelvis or the perineal area. Seventy-six patients presented with locoregional relapse only, and 19 patients presented with locoregional relapse and concomitant distant metastases. All patients were irradiated at the site of locoregional relapse. Total dose of irradiation was resp. 44 Gy median (range 6-66 Gy) and 40 Gy median (range 6-50 Gy). In the group of patients with locoregional relapse only, recurrence-free survival and survival after radiotherapy were, respectively, 23% and 61% at 1 year, and 6% and 13% at 3 years. In the group of patients with concomitant distant metastases, survival after radiotherapy was even worse, 33% at one year, and nihil at 3 years. Recurrences after radiotherapy occurred early during follow-up with 75% of the recurrences being recorded during the first year of follow-up. Recurrent or persistent disease inside the irradiation volume was the most important clinical problem in both groups, being documented in, respectively, 43/76 and 7/19 (7/13 if six patients were excluded with a survival of less than 3 months from onset of therapy). In the group of patients with locoregional relapse only, using recurrence-free survival as the endpoint, dose of irradiation (p = 0.01) was a significant multivariate prognostic factor and using survival as the endpoint, dose of irradiation (p = 0.005) and grade of tumor differentiation (p = 0.002) were significant. Potentials of current radiotherapy regimes are limited. Therefore, maximal initial treatment is warranted. In the event of a relapse after initial radical surgery, one should opt for either more aggressive standard therapy, or either new combined modalities approaches should be studied.