High resolution ultrasonography is an emerging technique for the investigation of peripheral nerves and is increasingly used worldwide in the diagnosis of peripheral nerve disorders, however, until now it is not widespread in Hungary. According to the literature this method is especially useful in entrapment neuropathies, traumatic peripheral nerve injuries, tumors of the peripheral nerves and sonographically guided interventions. Ultrasonography allows precise morphological analysis and quantitative measurements of the nerves providing useful complementary information to electrodiagnostic data. In entrapment neuropathies ultrasound shows nerve swelling mainly proximal to the sites of compression and a focal change of echotexture. On longitudinal scan, an abrupt caliber change and spindle-like swelling of the compressed nerve segment can be seen. Evaluation of the anatomical background and visualisation of the postoperative and posttraumatic changes provide useful information for planning of the therapy. Ultrasound may be of significant help in localizing the pathological nerve segment when it is at an electrophysiologically inaccessible site or when substantial secondary axonal loss precludes precise electrophysiological localization and it might even show pathological changes when nerve conduction studies are normal. Contrary to electrophysiological investigation ultrasonography might discover neurotmesis in the akute phase of traumatic nerve injuries indicating the necessity of surgical intervention. We provide a summary of the main indications and further application areas of this method.