PURPOSE: To determine the diagnostic accuracy of CT for the detection of cervical lymph node metastases in patients with papillary thyroid carcinoma (PTC). MATERIALS AND METHODS: Two hundred twelve consecutive patients with surgically proven PTC were included in this study. CT images were retrospectively evaluated to determine the presence of a node metastasis using morphologic CT criteria (at least one of the following: strong nodal enhancement without hilar vessel enhancement, heterogeneous enhancement, calcification, and cystic change). The diagnostic accuracy of CT for the diagnosis of a metastatic lymph node was assessed using a level-bylevel analysis. RESULTS: The accuracy of the CT finding for strong nodal enhancement was greater than the other morphologic CT criteria (81.6% and 74.5-78.5%, respectively). The sensitivity, specificity, and accuracy were 64.4%, 91.4%, and 84.3% by the morphologic CT criteria, and were 34.6%, 93.9%, and 78.2% by size criteria, respectively. CONCLUSION: The morphologic CT criteria are more accurate than the size criteria in the detection of cervical lymph node metastases in patients with papillary thyroid carcinoma; and, strong nodal enhancement on a CT scan is the most important factor for its diagnostic accuracy.