The genus Chaetogaster belongs to the subfamily Naidinae (Naididae), includes mostly species of small size and is diverse and abundant in surface coarse sediments in streams. The aim of the present study is to initiate an inventory of lineages of Chaetogaster in Switzerland. We used 135 specimens collected at six sites in four streams of four cantons. We sequenced the cytochrome c oxidase (COI) gene from all specimens and ITS2 and rDNA 28S from all or several specimens of each lineage delimited using COI data and preserved a voucher of almost all sequenced specimens. We could delimit one lineage (=species) for Chaetogaster diaphanus (Gruithuisen, 1828), three within Chaetogaster diastrophus (Gruithuisen, 1828), one for Chaetogaster langi Brestcher, 1896, one for Chaetogaster setosus Svetlov, 1925 and three unidentified Chaetogaster spp. Two lineages of Chaetogaster spp. could correspond to a new morphological group, but this should be confirmed on more specimens. We described the three C. diastrophus lineages and two Chaetogaster spp. as new species for science. The prospects of the present work are to complete the data of the molecular diversity of this genus in Switzerland and to describe on a molecular/morphological basis the new Chaetogaster species that we will probably find.