The last decade has seen the rise of the research fields of DNA analysis and population or ecological genetics.They have the potential to allow the revision of landscape ecological concepts such as habitat connectivity or fragmentation. In this chapter, we first ask how population genetics can support and extend landscape ecological research from analysing patterns to understanding processes, and we introduce the concepts of neutral and adaptive genetic diversity. We further outline relevant population genetic applications, provide corresponding examples and discuss the benefits and limitations of molecular techniques by referring to the topics of migration, dispersal and gene flow at various spatial and temporal scales. The discussion highlights migration patterns of species in the postglacial landscape, the assessment of historical dispersal and gene flow among populations, a description of how the current movement of plant propagules can be measured and a brief reassessment of the metapopulation concept and of what would be required to provide unequivocal empirical data on metapopulations. Despite the evident usefulness of molecular methods in landscape ecological research and the spatial context inherent to both landscape ecology and population genetics, the two fields have hitherto virtually stayed apart.Thus, we claim that the emerging field of landscape genetics, a marriage of population genetics with landscape ecology, should be given research priority, both theoretically and empirically.We expect a significant contribution of this field to basic and applied topics such as fragmentation and the management of natural ecosystems.