Mediastin pathology includes primary lesion and lymph node invasion. The exploration of this anatomical region remains difficult and even hazardous, particularly to obtain histological biopsies. No invasive diagnostic exploration (thorax tomodensitometry and positron emission tomography) allows a histological precision, so mediastinoscopy remains the gold standard in the mediastinum investigation. However, it is not deprived of risk. Recently, guided biopsies and real-time transbronchial needle aspiration by endobronchial ultrasonography (EBUS) have been shown to increase the diagnostic yield over conventional bronchoscopic techniques. Therefore, EBUS is a suitable alternative to mediastinoscopy in the diagnosis of pulmonary or extra-thoracic malignancy, in the staging of mediastinal lymphadenopathy, and in the evaluation of mediastinal response after induction therapy. In the present paper, we present this new diagnostic approach and clarify the current indications of EBUS.