The genus Marphysa (Annelida: Eunicidae) is represented by only three species, Marphysa sanguinea, Marphysa aegypti and Marphysa birgeri, in the Mediterranean Sea. Combining morphological, molecular data (16S rRNA and cytochrome c oxidase subunit I mitochondrial loci) and environmental information, we present the first Mediterranean report of Marphysa chirigota, based on the specimens collected at Radès Station (Gulf of Tunis, W Mediterranean). The current information on species distribution in Marphysa strongly supports that M. sanguinea inhabits hard bottoms and has a restricted distribution close to its type location (south English coast and nearby NE European Atlantic). Radès Station specimens and all those reported as M. sanguinea along the Tunisian coast were found in shallow water soft bottoms. Therefore, we suggest that the presence of M. sanguinea in Tunisia seems doubtful, and all species reports of Marphysa from Tunisia might correspond to M. chirigota.