The authors analyze their experience on 136 percutaneous biopsies of the lung performed on 80 patients during 3 years. Indications are given with particular reference to the technique, to the type of the needles used and the expedients adopted in order to reduce the complications. Patients to be subjected to biopsy should be correctly and carefully selected. To this purpose, the authors present a protocol used for the patients affected by localized or diffused, single or multiple pulmonary lesions. Percutaneous needle biopsy of the lung assumes a precise role in the numerous diagnostic studies on these patients. The technique is considered in some cases essential to the right management of the patient. In other cases, instead, it is considered superfluous or too risky for the presence of contraindications. As demonstrated by authors' experience, supported by others, the method has appeared easy to perform and apt to provide good diagnostic results.