Phylogenetic relationships among 8 members of the Sorex cinereus group (S. camtschatica, S. cinereus, S. haydeni, S. jacksoni, S. portenkoi, S. preblei, S. pribilofensis, and S. ugyunak) and S. longirostris were estimated using DNA sequence data from 2 mitochondrial genes, cytochrome b (1,140 base pairs) and nicotinamide adenine dinucleotide dehydrogenase 4 (582 base pairs). S. hoyi, S. monticolus, S. palustris, S. tenellus, S. trowbridgii, and S. vagrans also were included in our analyses. Phylogenetic analyses of the combined data recovered 2 major clades within the species group: a northern clade that includes the Beringian species (S. camtschatica, S. jacksoni, S. portenkoi, S. pribilofensis, and S. ugyunak), S. haydeni, and S. preblei and a southern clade that includes S. cinereus and S. longirostris. Mitochondrial DNA clades generally corresponded to previously identified morphological groups with 2 exceptions: inclusion of S. longirostris with S. cinereus in the southern clade and inclusion of S. preblei within the northern clade. With the exception of the 5 Beringian species, taxa were readily differentiated with strong bootstrap support in our topologies. We also noted phylogenetic concordance with the general ecological affiliations of each species; the northern clade generally includes xeric-affiliated species, whereas the southern clade includes species with mesic habitat affinities.