In the last 10 years, molecular techniques have revolutionized studies in biogeography and have spawned the field known as phylogeography or phylogenetic biogeography. These techniques allow estimates of dispersal and vicariance events based on taxon relatedness and their correlations with geological history. The techniques are primarily based on the polymerase chain reaction (PCR) and DNA sequencing of nuclear, mitochondrial and chloroplast genes, including the nuclear ribosomal RNA genes with both conserved and variable regions. In this talk, we discuss the molecular techniques and sequences used in estimating biogeographical patterns and present our data from higher fungi suggesting that North American and Eurasian species disjunctions are the consequence of vicariance events. We also present evidence, based on DNA sequencing for occasional dispersal events within this group of organisms and for centers of unusual biodiversity.