After the revision of Fet & Soleglad (2002), Euscorpius tergestinus (C. L. Koch, 1837) was considered a polymorphic species widespread from France to Croatia. In this study, we reconsidered the taxonomy of E. tergestinus s.str. based on morphological and genetic evidence, its range, and its original description. Euscorpius aquilejensis (C. L. Koch, 1837), stat. nov., previously synonymous with E. tergestinus, is elevated to species status herein. A preliminary phylogenetic analysis based on available GenBank 16S rDNA data shows a separate, basal position of E. aquilejensis and some other Euscorpius species, which implies that the subgenus Euscorpius s.str. is paraphyletic.