Molecular characterisation of Swiss maize landraces Switzerland with its Alpine valleys has a tradition for maize cultivation reaching back to the 17th century; more than 160 landraces are stored in the national genebank. It was our goal tocharacterize them genetically. The use of neutral molecular markers ensured characterization and grouping of genotypes without influences of environment and selection. The identification of possible doubles as well as the grouping of the material on the basis of genetic distance traits was achieved. The main groups identified related to material typical for cultivation south of the Alps and north of the Alps. These groups were further divided into multiple groups of accessions. The way accessions were grouped indicated that most exchange of maize material happened within the northern parts of the country, probably because maize was more difficult to cultivate under cool temerate climatic conditions. Based on the grouping of the accessions according to genetic distances and a software approach to maximize diversity in a subset of all accessions a core subset was defined to represent the diversity of Swiss maize in extensive trials in the future. The core subset definition was carried using available phenotypic information from growth chamber and field tests. These indicated that some interesting traits for early vigor exists in this material.