Pneumonia in patients with organ transplantation constitutes a very frequent cause of mortality, as a result precocious aetiologic diagnosis is indispensable. The bronchoscopic techniques, bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB), constitute fundamental procedures for these diagnoses. We begin this study with the aim of evaluating the profitability obtained with these procedures. 36 bronchoscopies were performed on 29 patients with organ transplantation, in all of them we realized BAL and in 20 TBB. We confirm the presence of pneumonia in 30 (in 15 of them we had performed TBB), the BAL was diagnostic in 20 cases (66.6%) and the TBB in 7 (46.6%). With both, BAL and TBB, we obtained a sensitivity of 80% and a specificity of 75%. We isolated 10 bacteria, 8 Citomegalovirus (CMV), 6 Pneumocystis carinii and 2 Aspergillus fumigatus. The BAL and the TBB contributed significantly in the aetiologic diagnosis of pneumonia in patients with organ transplantation, consequently we consider them basic tools in the management of these infections.