Ultrasonographic examinations to detect late cervical lymph node metastases were performed at follow-up examinations for 52 patients with head and neck cancer who had not received neck dissection. Using diagnostic criteria we established previously, we accurately diagnosed 24 nodes in 10 patients as late metastases; 21 of these were nonpalpable. Of 12 nodes in 8 patients that were diagnosed as nonmetastatic using ultrasound (US) before radical treatment of the primary tumor, 11 showed an increase in the minimal diameter, 9 showed an internal echo pattern shift from homogeneous to heterogeneous and, in 7, the echogenic hilus changed from present to absent. A diagnostic equation was used to calculate a predictive value λ for 146 nodes. Of these, 5 of 25 with a λ value of −1 ≤ λ, and 7 of 121 with a λ value of < −1 were late neck metastases. The incidence of late metastasis was significantly higher in nodes whose value was −1 ≤ λ. Thus, US examination appears useful for the follow-up of cervical lymph nodes in patients with oral and maxillofacial cancer. (E-mail: y-yusa@md.tsukuba.ac.jp)