Between March 1978 and March 1989, 419 patients with 439 moderately advanced or advanced primary squamous cell carcinomas of the head and neck received treatment with curative intent with twice-a-day radiotherapy (120 cGy per fraction with a 4- to 6-hour interfraction interval). Seventy-nine percent of the patients had AJCC stage III or stage IV cancers. The primary site in most patients was the oropharynx, hypopharynx, or larynx. All patients received radiotherapy alone to the primary site, with or without planned neck dissection after radiotherapy. Surgery at the primary site was reserved for salvage of radiotherapy failures. No patient received chemotherapy as part of the initial treatment plan. Total doses were 7440 cGy to 7920 cGy in the majority of patients. In 54 patients with oropharyngeal lesions, an interstitial implant was used to add a 1,000- to 1,500-cGy boost after the basic dose. Local control results were compared on a site-by-site and stage-by-stage basis with the results of continuous-course, once-a-day radiotherapy at the University of Florida; the control results were the same as or better than after once-a-day radiotherapy for each site and stage (T2 to T4). Severe complications of radiotherapy occurred in 4% of patients and correlated with tumor dose, T stage, and disease site (oropharynx or larynx/hypopharynx). The addition of a neck dissection 4 to 6 weeks after radiotherapy of patients with advanced-stage neck disease was accomplished with an acceptable rate of morbidity and significantly improved the rate of control of neck metastases compared with radiotherapy alone.