In this paper, the author investigates the oldest Slavic borrowings to Hungarian with regard to the reconstruction of the dialectal landscape of Slavic in the Carpathian Basin at the time when the Hungarian tribes arrived here at the end of the 9th century. According to some phonetic criteria, it seems that the Hungarians found two main Slavic dialects in their new homeland: the Pannonian Slavic with mixed West and South Slavic features and the Bulgarian Slavic.