en Internal Medicine Internal Medicine Original Research Original Research The technique of transbronchial lung biopsy (TBLB) has expanded the diagnostic yield of bronchoscopy . In this article we are presenting 54 patients with diffuse pulmonary parenchymal involvement who underwent this procedure during six years between June 1980 and December 1989. The diagnostic yield of this technique in diffuse pulmonary parenchymal disease is great and was 66 percent excluding nonspecific pulmonary fibrosis. Compared with other literature this is a good way of diagnosing interstitial lung disease which obviates the need for transcutaneous lung biopsy and thoracotomy. 87 91 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-753&slc_lang=en&sid=1 PARVIZ VAHEDI 20031947532846006470 20031947532846006470 Yes From the Department of Internal Medicine. Imam Reza Medical Center, Mashhad University of Medical Sciences, Mashhad, Islamic Republic of Iran.