To help clarify controversial phylogenetic relationships within the family Emberizidae, we sequenced 1238 bp of mitochondrial DNA from the cytochrome b gene and a flanking portion of ND5. Although the longspurs (Calcarius) and the snow buntings (Plectrophenax) have been grouped with the Old World buntings (Emberiza) in traditional classifications, our molecular phylogenies constructed with maximum likelihood and maximum parsimony place these genera basal to a clade in which the Old World buntings and North American sparrows are sister groups. Contrary to the hypothesis that the radiation within Emberiza is recent following a westward expansion of emberizid stock into Eurasia from North America, we found that the level of genetic divergence among Old World buntings approximates those among different genera in North American sparrows. Thus the radiation of the Emberizidae seems to have occurred at roughly the same time in the Palaearctic and Nearctic. Our results are consistent with earlier analyses of allozymes, but sequences from multiple genes and new morphological analyses are required to fully resolve phylogenetic relationships within the Emberizidae.