Nine additional sequences from representatives of different tribes of the family Bovidae were combined with six published artiodactyl sequences to provide orthologous mtDNA for investigation of bovid phylogeny and evolution. Each species was represented by a homologous 2.7-kilobase-pair stretch of mtDNA for the complete 12S and 16S rRNA genes and three adjacent tRNA genes. These data, when compared to other results, provided evidence for a monophyletic Bovidae and for two clades within the family: one including the tribes Boselaphini, Bovini, and Tragelaphini and another for an Antilopini/Neotragini grouping. All other intrafamilial relationships were only weakly supported. These sequence comparisons suggest that most bovid tribes originated early in the Miocene with all extant lineages present by approximately 16-17 million years ago. Thus, bovid tribes provide an example of rapid cladogenesis, following the origin of families in the infraorder Pecora.