We conducted a five-year review of our use of TBNA during bronchoscopy in our clinical practice. Out of 1,630 bronchoscopic procedures, 633 patients (39 percent) had TBNA performed as part of the initial examination. Mediastinal nodes were sampled in 86 percent of the patients who had TBNA performed, and 127 (23 percent) of 547 of these aspirates were positive. Other areas of mucosal abnormality of the tracheobronchial tree were also sampled by TBNA under direct vision and showed malignant cells in 44 (25 percent) of 176 aspirates. Of 363 patients first diagnosed as having carcinoma of the lung who had TBNA of N2 nodes, 41 (59 percent) of 70 with small-cell tumors were positive, as were 83 (28 percent) of 293 with non-small-cell malignant neoplasms. Comparison of cytologic results obtained by TBNA with histologic material in 109 cases showed an excellent correlation. In 31 cases (4 percent of all TBNA), the aspirate provided the sole means of establishing the diagnosis of cancer. Two patients were thought to have false-positive aspirates. No complications of therapeutic significance were encountered. We believe that TBNA is a safe and effective way to assess mediastinal lymphatic involvement in the staging of lung cancer and that TBNA can be safely performed as part of the initial bronchoscopic examination in patients suspected of having malignant neoplasms of the chest.