The authors describe the method of fibrobronchoscopy, bronchoalveolar lavage and transbronchial biopsy. They evaluate the results of transbronchial biopsies in 97 children where damage of the pulmonary interstitium was suspected. The pulmonary parenchyma was obtained by biopsy from 62 children (63.9%). Of these in 36 children some form of idiopathic interstitial pulmonary fibrosis was confirmed, in 6 children sarcoidosis (confirmed by cytological examination of perbronchial puncture and in one case by histological examination). In one instance exogenous allergic alveolitis was confirmed by histological examination and in four children haemosiderosis (2x siderophages in the bronchoalveolar lavage and 2x also by histological examination). In histologically confirmed findings the authors evaluate the bronchoscopic findings, they present the results of bronchoalveolar lavage (incl. evaluation of T lymphocytes - CD3 and CD4 a CD8 sub-populations). They conclude that BAL serves in IPCH in children for preliminary information although the correlation between the histological findings of TBB and cytological finding from BAL is relatively close. TBB is one of the possible ways how to verify damage of the pulmonary interstitium. In the authors’ opinion complete data on TBB and BAL in children with interstitial lung disease with evaluation of the endoscopic picture, BAL and histological findings were published for the first time.

        Key words: interstitial lung diseases in children, diagnosis, fibrobronchoscopy, bronchoalveolar lavage,