The Military Macaw (Ara militaris) and the Great Green Macaw (A. ambiguus) are species whose close relationship is reflected in their morphological similarity as well as their geographic ranges. Military Macaws have a disjunct distribution, found in Mexico as well as several areas in South America, while Great Green Macaws have two or more disjunct populations from Honduras to eastern Ecuador. We used mitochondrial sequence data to examine the phylogenetic relationships between these two species, and also among representative samples across their ranges. Our data clearly support recognition of the two species as being distinct evolutionary lineages, and while we found significant phylogeographic structure within A. militaris (between samples collected in eastern and western Mexico), we did not find any evidence of lineage divergence between A. ambiguus from Costa Rica and Ecuador.