The incidence and causes of radiotherapeutic failures and surgical salvage were analyzed by anatomical sites, staging of the primary lesion, modalities of treatment, and clinical features in 554 patients with squamous cell carcinomas of the oropharynx treated with megavoltage irradiation from 1954 through 1967. Differences in the incidence of failures were found by T staging, depending on the anatomical site. The presence of a necrotic ulcer was correlated with poor results. Systematic causes of geographical misses or underdosed areas were found in certain techniques. Specific precautions are outlined.