To determine the role of transbronchial needle aspiration (TBNA) in the diagnosis of peripheral pulmonary lesions, TBNA was performed in 20 patients who had unexplained nodules (15) or masses (five) and no endobronchial abnormality. The TBNA cytopathology was positive for malignancy in 11 patients, and provided the only diagnostic specimen in seven. The TBNA yield was significantly higher than that of forceps biopsy or bronchial brushing, either alone or in combination (p less than 0.05). The procedure was complicated by pneumothorax in one patient. Transbronchial needle aspiration is diagnostically useful and safe for evaluation of the peripheral pulmonary nodule.