In this paper we describe a new species of Hylomyscus based on molecular (Cyt b and 16S rDNA gene sequencing) andmorphometrical analyses. This new species occurs in Benin and Nigeria, and probably also in Togo. It differs by 8.29 to10.40 % of sequence divergence (K2P distance for the Cyt b gene) from all other species of the H. alleni speciescomplex, and can be distinguished from these species through morphometrical multivariate analyses. It differs significantly from its closest relative, H. simus, by four external and nine cranio-dental measurements. The role of riversand Pleistocene forest refugia in the diversification of the H. alleni species complex is discussed.