CT staging of mediastinal lymph node metastases from bronchogenic carcinoma is a subject of considerable controversy. The frequency of metastases to normal-sized lymph nodes is a critical issue related to the sensitivity of CT. The authors prospectively examined 42 patients with bronchogenic carcinoma with CT; in 39, careful surgical-pathologic correlation of mediastinal lymph node status was possible. Only 7% had metastases limited to mediastinal lymph nodes that were normal-sized at CT. This reflected a low overall frequency of metastases to normal-sized nodes and several diagnostic factors that converted potentially false-negative studies into true-positive CT studies. In this small series, metastases to enlarged nodes were more likely to have extracapsular spread of tumor, a poor prognostic factor. Overall, the authors do not consider metastases to normal-sized mediastinal lymph nodes to be a major problem in CT staging of non-small cell lung cancer.