Endoscopic sonography belongs to the most dynamically developing diagnostic and therapeutical methods in gastrointestinal and pancreatobiliary endoscopy. Its big advantage is the nearness to the wall of digestive tube and closed organs without disturbing elements as air or adipose tissue. Whereas originally it was designed for diagnostics of pancreas diseases, at present its indications have widened significantly and they are widening further. With help of FNA or core-biopsy it is able to increase its accuracy significantly in differential diagnostics of many diseases. Increasingly it finds its application also as a therapeutical method. Blockage or neurolysis of coeliac plexus as well as transgastric or transduodenal drainage of pancreatic pseudocysts are already part of routine endoscopic practice at many workplaces.