During the systematic floristic research along Transdanubian roads (NW Hungary) since 2013, two native halophyte Spergularia species has been found. Due to the well known spreading near motorways in Eastern-Central Europe, the appearance of Spergularia marina along roads in north-western Hungary is not a surprise. Occurrences of the species were registered along fourteen main roads. Some of the stands are very rich where S. marina forms single-species lines along the asphalt edge. The spreading of Spergularia media along roads is yet much less intensive. Four stands were found near the motorways M1 and M7, main road 74, and the common section of the main road 86-87. Both species are native in the Hungarian plains, being specific elements of Pannonic alkali grassland associations, however, their secondary migration along road edges is promoted by road salting, intensive management of roads and increased vehicle traffic. In this paper, we specify secondary occurrences of the two Spergularia species, discuss their ecological and abiotic circumstances and publish corresponding distribution maps. Due to recognition problems in Spergularia, a corrected determination key was provided.