A comparison was made of clinical diagnosis by ultrasound (US) and CT examination in 52 patients who had undergone radical neck dissection. The site, size, depth and other patterns concerning the nodes which could not be detected by physical examination was examined. US and CT examination proved superior to conventional clinical examination in detecting metastatic nodes. US and CT revealed that the disease stage in nine necks had increased from N1 to N2b and in seven of 11 necks from N0 to N positive. The characteristic features of US and CT diagnosis of metastatic lymph nodes were elucidated. Specifically, the diagnosis of cervical metastatic nodes by a combination of US and CT was found to be the most reliable method for detection of subclinical lymph nodes.