Résumé : The purpose of this randomized trial was to verify some experimental and clinical data suggesting a possible potentiating effect of bleomycin when used concomitantly with radiotherapy. Out of 220 patients with a biopsy proven epidermoid carcinoma of the oropharynx, 186 evaluable cases are reported here. One group of 87 patients was treated with radiotherapy alone (Cobalt 60 ∼ 6400 rad ∼ 7-8.5 weeks), the other group of 99 patients received radiotherapy combined with bleomycin, the latter administered at the dose of 15 mg i.m. twice a week for 5 weeks (total dose: 150 mg). Analysis of the treatment groups showed their comparability with regard to the most important prognostic factors (TNM, sites of primary, sex, age ...). Complication rates of mucositis and epidermitis were significantly increased (71%) in the radiotherapy + bleomycin group and were considered responsible of frequent denutrition and weight loss in this group. Such side effects necessitated a delay of radiotherapy in 22% of patients and definitive interruption in 5% in the combined treatment group whereas in the radiotherapy alone group no interruption of treatment was recorded and only 5 treatments (6%) were postponed. Considering tumor regressions measured 6 weeks after completion of radiation therapy, total regression rates were not significantly different in both groups as far as primary tumor (67.9-67%) or neck nodes (49-62%) are concerned. Survival curves obtained by the actuarial method showed the same 50% survival in both groups at 15 months of follow-up. © 1977.