ABSTRACT. – A new species belonging to the genus Eupolymniphilus (Sabelliphilidae) is described from an anchialine cave located on the southern coast of the Tyrrhenian Sea (Central Mediterranean). Among the six species recognized in the genus, the new species E. mediterraneus sp. nov. is most closely related to E. orientalis, E. brevicaudatus and E. occidentalis in sharing the following characters: proximal caudal seta swollen proximally, antennal second segment with pointed outer distal corner, and mandible with 1 scale on convex side. A comparison with the most closely related species reveals that the new species differs in total body length and in length/width ratio of the caudal ramus. The total body length is 0.75 mm and the caudal ramus is 3.0:1 times longer than wide, whereas in E. orientalis, E. brevicaudatus and E. occidentalis, the abovementioned characters are: 0.88-1.04 mm, 1.50:1; 1.03 mm, 1:1; and 1.17-1.21 mm, 2.69:1, respectively.