A new species of bivalve belonging to the family Vesicomyidae, Laubiericoncha puertodeseadoi, n. sp., is described. The material was collected during several cruises to the continental margin of Argentina on board of the R/V “Puerto Deseado”. The distribution of the genus Laubiericoncha is expanded to include the southwestern Atlantic Ocean. The description was done by using morphological characters of the shell and mantle cavity organs. All type material of congeneric species was examined and illustrated. Laubiericoncha puertodeseadoi, n. sp., is characterized by a compressed, subrectangular, elongated, inequilateral shell, with slightly prosogyrous umbo and a well-defined triangular pallial sinus, strong external ligament and ctenidia with two robust demibranchs, foot anteriorly projecting and fused siphons. This new species constitutes the first record of the genus Laubiericoncha living on the continental margin off Argentina.