We report two successful remnant and recurrent cases of head and neck cancer treated with S-1. Case 1, a 52-year-old man, was diagnosed as supraglottic laryngeal carcinoma (T3N2cM0, squamous cell carcinoma: SCC) on January 25, 2000, and concurrent chemoradiotherapy (CCRT) was applied. After the treatment, a remnant tumor in the larynx was found by biopsy. He was followed using UFT at 400mg/day because he had refused surgery. Pulmonary metastasis was detected by chest CT on June 14, 2001, and the administration of S-1 was started. After 2 courses, the mass in the lung disappeared, and the primary lesion was also judged to be a complete response(CR). The administration of S-1 is still continuing and remnant tumors have not been found. Case 2, a 76-year-old man, was diagnosed with hypopharyngeal carcinoma (T3N2bM0, SCC) on December 14, 2001, and CCRT was applied resulting in CR in the hypopharynx and the neck. He was followed using UFT at 300 mg/day after discharge. A supraclavicular lymph node became palpable on March 27, 2003. Pathological examination by fine needle aspiration cytology showed SCC, class V. After 2 courses administering S-1 at 100mg/day, the supraclavicular lymph node disappeared. S-1 was changed to UFT at 300 mg/day on July 31, 2003, because adverse events of grade 3 appeared. Administration of UFT was continued for one year. No recurrence has been found for 5 years.