Molecular phylogenetic methods were used to examine a number of morphologically based hypotheses concerning the taxonomic relationships and origin of the grasshopper subfamily Melanoplinae. This paper focuses on several North American genera and their interrelationships and connections with taxa on other continents. Portions of four mitochondrial genes (coding for cytochrome b, cytochrome oxidase subunits I and II, and NADH dehydrogenase subunit II) were sequenced in 17 North American species representing 13 genera, along with five and eight species from South America and Eurasia, respectively. Phylogenetic trees were constructed using maximum parsimony, weighted parsimony, neighbor-joining, and maximum likelihood methods. Bootstrap replications provided levels of confidence for recovered associations. Maximum resolution was achieved using weighted parsimony and by treating all sequences, totaling 1716 bp, as a unit. In terms of taxonomic organization, our phylogenetic analysis demonstrated that an earlier division of Melanoplinae into two tribes, Melanoplini and Podismini, has merit. Monophyly of each tribe was supported statistically. There was, however, no support for various systems subdividing Podismini into subtribes or “groups.” Neither eastern nor western North American podismines proved monophyletic. There was no support for the integrity of another proposed tribe, Dactylotini. All methods suggested South America as the place of origin for the subfamily, supporting previous molecular studies. Both tribes originated in North America, most probably in the southwest United States. With respect to Podismini, this is contrary to the prevailing view of a Eurasian origin for the tribe.