The frequency of iatrogenic pneumothorax is high in acquired pneumothorax. Bronchoalveolar lavage (BAL) is a method of evaluating materials taken from the tracheobronchial system by bronchoscopy. The complication rate in BAL procedure is below 5%. These complications are pneumonia, temporary alveolar infiltration, bronchospasm, hypoxia and alveolar hemorrhage. Pneumothorax is a very rare complication of BAL. In our study, we aimed to report a very rare case of pneumothorax that developed after BAL.