Endoscopic ultrasound (EUS) has evolved in recent years into a technique with a major clinical impact in digestive and mediastinal diseases. In fact, EUS has represented a major advance in the diagnosis and staging of several tumors, and can determine a change in diagnosis and management in 25% to 50% of cases. EUS also provides guidance for fine-needle aspiration of almost all lesions detected during a standard procedure. In addition, several new diagnostic techniques associated with EUS have being developed over the last years, such as EUS guided elastography, contrast-enhanced EUS, and EUS-guided biopsy that are very useful for the differential diagnosis of solid lesions. These techniques are becoming essential in clinical routine. EUS-guided therapy is also increasing in terms of new indications, such as drainage procedures, tumor ablation and injection techniques. Although these procedures are being used in the clinical practice of specialized centers, there is a need for producing research data and increasing the knowledge in these fields.