This report describes a complete response to a chemoradiotherapy regimen in a child with an advanced and unresectable squamous cell carcinoma of the tongue. An 8-year-old girl had stage 4 squamous cell carcinoma of the tongue (T4N2M0), causing severe trismus and dysphagia. She received hyperfractionated external beam radiotherapy (total 74.4 Gy) and concomitant intravenous infusion of hydroxyurea (0.313 mg/m2 per min) for 43 days. Grade 3 mucositis and myelosuppression were the main toxicities. There was marked symptomatic improvement, and the patient achieved a complete response. She is disease-free 24 months after treatment, and all the acute symptoms have resolved. The regimen was well tolerated with acceptable toxicity and led to a complete objective response. This regimen needs further evaluation to confirm its efficacy and to ascertain its long-term effects in children.