This is the first volume(text volume) of two of a generic revision of the American Zyganidae Lattreille, 1809. Most of the availbale type material was checked. 5 new genera and 24 new seocies are described and 137 taxonomical and nomenclatorical changes have been done.The main characters and their variability and value for taxonomical, systematical and phylogenetical studies are discussed. A checklist for all described taxa and a key to the genera is given. Moreover, new information on the biology, genitalia morphology and wingscale ultrastrucutre is provided.