To estimate the accuracy of different radiologic criteria used to detect cervical lymph node metastasis in patients with head and neck carcinoma, seven different characteristics of 2,719 lymph nodes in 71 neck dissection specimens from 55 patients were assessed. Three lymph node diameters, their location, their number, the presence of a tumor, and the amount of necrosis and fatty metaplasia were recorded. The minimal diameter in the axial plane was found to be the most accurate size criterion for predicting lymph node metastasis. A minimal axial diameter of 10 mm was determined to be the most effective size criterion. The size criterion for lymph nodes in the subdigastric region was 1 mm larger (11 mm). Groups of three or more borderline nodes were proved to increase the sensitivity but did not significantly decrease the specificity. Radiologically detectable necrosis (3 mm or larger) was found only in tumorous nodes and was present in 74% of the positive neck dissection specimens. Shape was not a valuable criterion for the radiologic assessment of the cervical lymph node status.