Thoracoscopy has received increasing attention over the past decade as a result of the considerable advances that have been made in the development of endoscopic instruments. In contrast to the newly established video-assisted thoracoscopic surgery, the classic way to perform thoracoscopy is using only local anesthesia and sedation (medical thoracoscopy) making the procedure less invasive and expensive. The leading diagnostic indication for medical thoracoscopy today is an exudative pleural effusion of unknown origin offering a yield of more than 90% in malignancy or tuberculous pleurisy. In addition, talc poudrage during thoracoscopy is the most effective way to perform pleurodesis. For spontaneous pneumothorax, the second most important indication, medical thoracoscopy allows staging as well as therapeutic measures such as coagulation of blebs or talc poudrage. Other indications such as biopsy for diffuse lung disease or peripheral nodules are now reserved for video-assisted thoracoscopic surgery.