The worldwide family Mactridae Lamarck, 1809, is well represented in the southwestern Atlantic Ocean. Literature research revealed 22 living nominal species linked to Magellanic forms. Within this context, a taxonomic revision of the species belonging to the family Mactridae that inhabit the Magellanic area was carried out. The analysis was done by using morphological characters of the shell and describing the mantle cavity organs. After extensive fieldwork from Peninsula Valdés to Tierra del Fuego province, seven valid living species were confirmed. Synonymies of those valid forms have been updated, as have their geographic distributions. Redescriptions of the species here considered as valid, i.e.: Mactra fuegiensis Smith, 1905, Mulinia bicolor Gray, 1837, Mulinia byronensis Gray, 1837, Mulinia edulis (King & Broderip, 1832), Mulinia exalbida Gray, 1837, Mulinia levicardo (Smith 1881) and Darina solenoides (King & Broderip, 1832) are provided.