MEDIASTINOSCOPY is an endoscopic examination of the anterior mediastinum that is extremely uncomplicated but which yields useful information. The technique has been described before 1,2 and must be rigidly adhered to in all aspects. The salient points of the examination are briefly reviewed. After obtaining anesthesia, a transverse incision is made in the suprasternal area. This dissection is carried down to the anterior tracheal surface inferior to the thyroid isthmus. It is now important to carefully incise the last layer of pretracheal fascia. Once below this fascia, blunt finger dissection proceeds caudally on the anterior tracheal surface. This blunt dissection creates a pocket into which the mediastinoscope is inserted. The scope is further advanced under direct vision by enlarging the pocket with a velvet-eye suction tip. Tissue that is to be biopsied must first be tested for vascularity. This is done by aspirating through the mediastinoscope with a long