A large number of Red Sea species are colonizing the eastern Mediterranean Sea after the opening of the sea-level Suez Canal in 1869, mainly following the Levantine and Anatolian coasts and then spreading westwards, at least in part, by shipping transport of larvae, juveniles, or adult specimens. Two of them are Cerithium scabridum and Fulvia fragilis, well established along the Italian coasts, where new large and stable populations have formed. Some other species, such as Anadara demiri, were accidentally introduced through shipping in our seas and have found good conditions to survive and develop. New distributional and ecological data about these alien molluscs are given and all the species found in association are listed to improve understanding of their living biocoenosis. The presence of a further lessepsian mollusc and of an intentionally introduced species, Brachidontes pharaonis and Ruditapes philippinarum, was also confirmed respectively from Vibo Valentia harbour and from the Gulf of Naples and the Gulf of Taranto. The nomenclature used is based on the CLEMAM Database (last research on 9 January 2008).