Endoscopic ultrasound (EUS) has been developed since the early 1980s. Its clinical role in the diagnosis of gastrointestinal wall lesions and staging of gastrointestinal and lung cancer has evolved over the last two decades. Initially, it was either used as an imaging tool for gastrointestinal wall lesions or for staging of gastrointestinal tumours. However, in combination with fine-needle aspiration under real-time scanning, EUS is now being used in tissue sampling for diagnosis. In addition, EUS may be used therapeutically in coeliac plexus neurolysis or pseudocyst drainage. This review concentrates on the current applications of EUS.