Simple SummaryMites from the family Laelapidae are frequently associated with small mammals, mainly rodents, and can be found on their body surface or in their nests. Classification of the Laelapidae is complicated because of high levels of their morphological and ecological variability. This study aimed to undertake molecular characterization and to assess the phylogenetic relationship among eight Laelapidae mite species collected from different rodent hosts in Lithuania, Norway, Slovakia, and the Czech Republic using the nuclear and mitochondrial molecular markers. Our study provides new molecular data onLaelaps agilis,Laelaps hilaris,Laelaps jettmari,Haemogamasus nidi,Eulaelaps stabularis,Hyperlaelaps microti,Myonyssus gigas, andHirstionyssussp. mites collected from seven different rodent hosts and three geographical regions in Europe. This study, for the first time, registered sequences of four mite species:H. microti,Hirstionyssussp.,M. gigas, andE. stabularis.AbstractThe family Laelapidae (Dermanyssoidea) is morphologically and ecologically the most diverse group of Mesostigmata mites. Although molecular genetic data are widely used in taxonomic identification and phylogenetic analysis, most classifications in Mesostigmata mites are based solely on morphological characteristics. In the present study, eight species of mites from the Laelapidae (Dermanyssoidea) family collected from different species of small rodents in Lithuania, Norway, Slovakia, and the Czech Republic were molecularly characterized using the nuclear (28S ribosomal RNA) and mitochondrial (cytochrome oxidase subunit I gene) markers. Obtained molecular data from 113 specimens of mites were used to discriminate between species and investigate the phylogenetic relationships and genetic diversity among Laelapidae mites from six genera. This study provides new molecular data onLaelaps agilis,Laelaps hilaris,Laelaps jettmari,Haemogamasus nidi,Eulaelaps stabularis,Hyperlaelaps microti,Myonyssus gigas, andHirstionyssussp. mites collected from different rodent hosts and geographical regions in Europe.