Lung cancer without distant metastasis often requires an invasive surgical procedure to document inoperability. In order to determine how often puncture biopsy was a valid substitute for a surgical procedure, we investigated the performance of endoscopic staging by means of transcarinal needle aspiration biopsy during rigid bronchoscopy. Eighty lung cancer patients with subcarinal lymph nodes visible on computed tomography (CT) scan were studied. Specimens were of histological quality (i.e. lymph node tissue) in 59 out of 80 (74%) patients, and showed malignant invasion of this lymph node tissue in 43 cases. Specimens of cytological quality (i.e. lymph node cells) were obtained in 13 out of 80 (16%) patients, and showed malignancy in 7 cases. Therefore, adequate evaluation of the subcarinal lymph nodes was possible in 72 out of 80 (90%) patients. In 50 of these 72, malignant mediastinal spread was proven, and further invasive surgical staging could be avoided. Subgroup analysis showed that this outcome tended to be more likely in patients with abnormal endoscopic appearance of the main carina, with locally extensive tumours, and with nonsquamous histology. These results indicate that transbronchial needle aspiration biopsy of subcarinal lymph nodes can be a valuable alternative to more invasive surgical staging in patients selected by CT scan.