In order to assess the number of lymph nodes dissected in a radical neck dissection, a retrospective study was conducted by reviewing the clinical and pathology records. From April 1990 to November 1994, 20 head and neck squamous cell carcinoma patients received neck dissection in the Department of Otolaryngology, Sun Yat-Sen Cancer Center, the number of lymph nodes identified and recorded in pathology reports were reviewed. An average of 32.9 lymph nodes were discovered in twenty patients. The site, patient sex and operative procedure did not affect the result. However, the average number of lymph nodes in 6 previously irradiated patients was 22, while that of 14 patients without prior irradiation was 37.6. The difference was probably related to severe fibrosis of soft tissue and lymph nodes after radiotherapy.