Beyond their public health importance and prominent role in toxinology, rattlesnakes have enjoyed increasing popu- larity as model organisms in a wide range of biological disciplines. Perhaps surprisingly, however, our understand- ing of the phylogeny of the group has lagged far behind that of many other, often much less iconic taxa. While the placement of rattlesnakes among pitvipers appears largely resolved, we remain without a comprehensive, robustly supported phylogenetic hypothesis for the clade, despite a number of recent studies. In contrast, rattlesnakes have been common subjects for phylogeographic studies, which have yielded important insights into biogeographical patterns and processes in the New World. Both molecular and morphological studies have provided evidence that the standard classification of rattlesnakes in place for much of the 20th century underestimated their diversity, and a number of additional species have been described or newly recognized since the beginning of the 21st century. New molecular genetic, genomic and bioinformatic approaches promise a rich yield of new data to resolve questions of phylogeny and intraspecific population structuring.