Medical thoracoscopy allows the respiratory physician access to inspection and biopsy of the pleura. The method has several names, such as pleuroscopy, non-intubated thoracoscopy and exploratory thoracoscopy, all of which cover the same procedure. The main indication for medical thoracoscopy is the diagnosis of recurrent pleural effusion, where pleural biopsy is needed. Medical thoracoscopy differs from thoracic surgical surgery as patients are sedated rather than in general anaesthesia. This is a review of the state of the art of pulmonological investigations of recurrent pleural effusion and the important role of medical thoracoscopy.