Between 1972 and 1986, 123 patients were treated with curative intent for a metastatic squamous cell carcinoma in cervical lymph nodes of an unknown primary. The lesions, staged according to the 1987 AJC classification were 24 N1, 59 N2, 34 N3 and 6 Nx. A hundred four patients underwent a cervical lymph node dissection and 9 an adenectomy. All these patients received post-operatively external beam therapy on the Waldeyer ring, the pharyngo-larynx, the cervical nodal areas (45 Gy); a boost (20 Gy) was delivered to nodes presenting with extracapsular spread. The 10 remaining patients were inoperable and were treated by radiation therapy alone to a total tumor dose of 70-75 Gy. In the group treated by surgery-radiation therapy, the 5-year overall nodal failure rate was 13.7% and it was 60% for the patients treated by radiation therapy alone. For the first group, this failure rate was correlated to the AJC stage (p = 0.01) and to the number of histologically involved nodes (p = 0.05). The failure rate was 7.7% if the node was clinically fixed versus 21% if it was not (p = 0.07). It was 18% when there was an extracapsular spread and 4.3% when it was absent (p = 0.11). Thirteen patients developed a subsequent primary lesion, in pre-irradiation volume in 5 cases (4%).(ABSTRACT TRUNCATED AT 250 WORDS)