Nine strains of a Rodentibacter-related bacterium were isolated over a period of 38 years from a laboratory mouse (Mus musculus), seven laboratory rats (Rattus norvegicus) and a Syrian hamster (Mesocricetus auratus) in Düsseldorf and Heidelberg, Germany. The isolates are genotypically and phenotypically distinct from all previously described Rodentibacter species. Sequence analysis of 16S rRNA and rpoB gene sequences placed the isolates as a novel lineage within the genus Rodentibacter. In addition to the single-gene analysis, the whole genome sequence of the strain 1625/19^T revealed distinct genome-to-genome distance values to the other Rodentibacter species. The genomic DNA G+C content of strain 1625/19^T was 40.8mol% within the range of Rodentibacter. At least six phenotypic characteristics separate the new isolates from the other Rodentibacter species, with Rodentibacter heylii being the most closely related. In contrast to the latter, the new strains display β-haemolysis and are β-glucuronidase, d-mannitol and sorbitol positive, but fail to produce lysine decarboxylase and trehalose. The genotypic and phenotypic differences between the novel strains and the other closely related strains of the genus Rodentibacter indicate that they represent a novel species within the genus Rodentibacter, family Pasteurellaceae, for which the name Rodentibacter haemolyticus sp. nov. is proposed. The type strain 1625/19^T, (=DSM 111151^T=CCM 9081^T), was isolated in 2019 from the nose of a laboratory mouse (Mus musculus) in Düsseldorf, Germany.