To test the influence of various species traits, elevation and phylogeographical history on the genetic diversity of high-mountain plants in the Alps and Carpathians. The regular sampling grid comprised the whole range of the European Alps and the Carpathians. Twenty-two high-mountain plant species were exhaustively sampled and their genetic diversity was assessed with amplified fragment length polymorphisms (AFLPs). ANOVAs were used to check for relationships between species traits and species genetic diversity, and to test whether genetic diversity was influenced by altitude and phylogeographical history (i.e. Alps versus Carpathians). In both mountain systems, species dispersed and pollinated by wind showed higher genetic diversity than species with self or insect pollination, and with animal- or gravity-dispersed seeds. Only in the Alps did altitudinal range size affect species genetic diversity significantly: species with narrow altitudinal ranges in the highest vegetation belts had significantly higher genetic diversity than those expanding over wide altitudinal ranges. Genetic diversity was species specific and significantly higher in the Alps than in the Carpathians, but it was not influenced by elevation. Wind pollination and wind dispersal seem to foster high genetic diversity. However, species traits are often associated and their effects on genetic diversity cannot be clearly disentangled. As genetic diversity is species specific, comparisons across species need to be interpreted with care. Genetic diversity was generally lower in the Carpathians than in the Alps, due to higher topographical isolation of alpine habitats in the Carpathians and this mountain massif's divergent phylogeographical history. Elevation did not influence genetic diversity, challenging the long-held view of decreasing genetic diversity with increasing elevation in mountain plants.