Over several thousand years, landraces of hexaploid wheat have developed under a variety of different edaphic and climatic environments. This has led to the evolution of a large number of ecotypes adapted to specific local environments, which are certainly an important source of genetic variation in wheat. In this study, 30 SSR markers were used to characterize 478 hexaploid wheat landraces collected from 51 different countries. Substantial levels of genetic variation was found in the selected materials. The average number of alleles per locus across the entire set of landraces was 13.7. The highest level of gene diversity was observed in landraces collected in the countries from the Middle East, Europe and Asia, which is in agreement with the long history of wheat in these countries. It could be clearly demonstrated that genetic differentiation was closely correlated with geographical origin. The expansion of wheat culture from the Fertile Crescent to Europe, Africa and Asia, as evident from archaeological finds, could be confirmed with the SSR data. Neighbor joining clustering showed a clear separation between the European and the Asian wheat germplasm. Germplasm from European countries formed two sub-clusters (North Western and Central Europe and Mediterranean) which could reflect the oldest migration routes of the Neolithic farmers. The first route was carried out adjacent to the Mediterranean coast, while the second passed northwards across the Balkans to central, western and northern Europe. The relative position of landraces from the USA, Canada, and Australia/New Zealand clearly confirmed the European origin of North American and Oceanic wheat, which were introduced into these countries during the sixteenth and the nineteenth centuries, respectively. The location of African landraces within European and Asian germplasm clusters confirmed the establishment of wheat by early settlers from Europe and the East Indies.