Three hundred and twenty-two patients with inoperable squamous cell carcinomas of the head and neck were entered on a randomized study comparing "mixed beam" radiation therapy with photon radiation therapy. Patients with histologically proven tumors of T-stage T2, T3, or T4 and any N-stage originating in the oral cavity, oropharynx, supraglottic larynx, or hypopharynx were eligible. One hundred forty-five patients were randomized to photon treatment and 177 were randomized to mixed beam treatment. No significant differences could be demonstrated between the experimental and control groups for primary tumor control or overall survival, although there was an advantage for mixed beam treatment over photon treatment for patients with metastatic cervical adenopathy (69 vs. 55% complete response rate in the nodes, p = .024). It is concluded that mixed beam radiation therapy does not offer a significant advantage over photon radiation therapy for patients with advanced squamous cell carcinomas of the head and neck.