<p>This study explores the genetic diversity of the edible dormouse (<i>Glis glis</i>), a rodent species closely associated with deciduous and mixed woodlands rich in oak and beech trees. The research investigates the phylogeographic patterns and genetic structure of <i>G. glis</i>, particularly focusing on the genetic diversity within Romanian populations and their relationship to other European lineages. Mitochondrial cytochrome b gene sequences have been used to analyze genetic diversity and phylogenetic relationships. We collected 117 samples from various Romanian populations and combined them with the existing GenBank data to provide a broader geographical context. We confirm the existence of distinct phylogenetic lineages within <i>Glis glis</i>, highlighting a pattern of low to moderate genetic diversity within the Romanian populations. Five haplotypes were identified across the analysed Romanian populations. Two of these, Hap_2 and Hap_5, were shared with other European populations, Hap_2 being the most common haplotype in the European lineage. The remaining three haplotypes were unique to Romania, Hap_1 being found in Southern Romania, Piscoiu site, and Hap_3 and Hap_4 from Dobrogea (South-Eastern Romania). The widespread Hap_2 was shared by almost all analysed populations, with the exception of Piscoiu. The findings contribute to the understanding of the genetic structure of this species and have implications for future conservation planning.</p>