We report a case of a 54-year-old man with unknown primary squamous cell carcinoma in the bilateral neck. The patient was treated with chemotherapy and radiation therapy, because his right common carotid artery was invaded by the right neck tumor, and a complete curative operation was not considered possible. We chose instead combination chemotherapy with nedaplatin, adriamycin and 5-fluorouracil (NAF), because it was reported that NAF was available for advanced squamous cell carcinoma of the esophagus. After 3 cycles of NAF chemotherapy, the patient showed a partial response of approximately an 86% decrease in the right neck tumor for over three months. In addition to NAF, radiation therapy was performed. In the CT findings after chemotherapy and radiation therapy, the patient showed a complete response in the bilateral neck tumors. Unknown primary squamous cell carcinoma in the neck has been treated by combination therapy consisting of chemotherapy, radiation therapy and surgery. The regime of 5-fluorouracil and cisplatin is said to be an effective treatment for unknown primary squamous cell carcinoma in the neck. Based on our experience, NAF would be available as chemotherapy for unknown primary squamous cell carcinomas in the neck.