Therapeutic plasma exchange (TPE) is an extracorporeal blood purification technique to remove large molecular weight substances. Since the late seventies TPE was used in a variety of diseases in which humoral factors may play a part in the pathogenesis. Today, accepted indications only exist for a few entities in defined situations: Anti-glomerular basement membrane antibody mediated disease, TTP/HUS, Guillain-Barré-syndrome, hyperviscosity syndrome, chronic polyneuropathy associated with IgG and IgA gammopathy, chronic inflammatory demyelinating polyneuropathy and myasthenia gravis.