A brief synthesis of the systematics of the Myliobatídae and Dasyatidae occurring in the littoral water of the Province of Buenos Aires (north of the Argentina Sea) is given. Descriptions based in numerous specimens, meristic tables and food habits of Myliobatis goodei Garmau, 1885, M. freminvillei Lesueur, 1824 aud Dasyatidae pastinaca (Linné, 1758) are given. The external and interna! morphology of the appendices genitales are considered.