Radial endobronchial ultrasound (EBUS) improves the sonographic diagnostics of the mediastinum and the staging in patients with lung and non-lung cancer. The use of EBUS allows visualization of the tracheobronchial wall and the immediate surrounding structures in a high resolution. Since it can determine the true thickness and extent of a tumor, this technique already influences the endoscopic treatment of pulmonary malignancies in early and advanced cancers in many centers. Especially in cases with early stage lung cancer EBUS should be considered state of the art and be used as a selection criterion for photodynamic therapy or other local treatments in future. EBUS has increased the yield of flexible bronchoscopy in the diagnosis of solitary pulmonary nodules. The use of this guidance technique in combination with a guide sheath as an extended working channel may provide a means for therapeutic interventions. The ultimate goal of minimally invasive treatment of peripheral lung lesions in inoperable patients now appears feasible.