This article sums up an analysis of the entries dated 1480-1498 from the Customs Register of the borderposts at Stara Wies Spiska and Lubowla. It is a detailed record of Polish goods brought from Poland to the town of Kiezmark as well as those exported by the Kiezmark merchants across the Carpathian Mountains to Poland. The book, though only parts of it are extant, is Poland's earliest customs register, which not only documents the country's foreign trade but also contains unique information about the merchants and carriers (vectores), the description of the goods and their destination. There are also notes about the way the merchandise was moved, packaged, and made secure during transport. An analysis of the entries has revealed the names (and surnames) of over one hundred traders from Kiezmark and as many names of carriers (seventy-five of them from various places in Poland). They were active all year round, but business tended to peak in late autumn and in winter, when heavy goods could be moved on sleighs. Exports from Poland (chiefly lead, malachite, salt, hops, wax, honey, edible oil, fish, animal skins and furs, perfumes, pepper, cinnamon, ginger, laurel leaves and other condiments) far exceeded the imports (copper, iron, steel, copperware, wine and horses). We can also find highly interesting entries about trade in paper and books (no doubt the latter originated from Cracow, the leading centre of the printing trade in Central Europe). In addition to its lists of goods that were taken across the border the Spisz Customs Register notes their prices (an important piece of evidence which, matched with other contemporary sources, could well be the subject of a separate study). It also records data which enable us to trace the drift of cross border migrations, from Poland to the Spisz towns of Kiezmark and Lewocza. Above all, however, that late fifteenthcentury customs register demonstrates that in the Middle Ages the Carpathians were hardly a formidable barrier between Poland and Hungary (Slovakia). The mountain range did not prevent the two nations from developing numerous political and cultural ties; nor did it prove to be a major obstacle to the flow of trade.