Percutaneous fine-needle aspiration biopsy of the lung is a relatively simple invasive procedure with good patient acceptance, low morbidity, and almost negligible mortality. It provides a diagnosis of pulmonary, hilar, and mediastinal masses quickly and accurately, eliminating many laboratory tests and saving hospital days, thereby saving time and money. Percutaneous fine-needle aspiration biopsy should be performed early in the investigation of many types of intrathoracic lesions.