The abundance and wide distribution of mullets in the tropical, subtropical, and temperate regions of all continents make them a very important commercial species in fisheries and aquaculture of many regions in the world. However, the similar morphology among several species that inhabit all oceans makes it difficult to accurately determinemorphological differences between mullet species. The objectives of the present study were to identify the different species of mullets from the Atlantic coast of the South Caribbean and South America using six mitochondrial genes and to test the hypothesis that Mugil liza is widely distributed in this region. The results indicated the existence of eight groups among our Atlantic samples, and two of them are possibly new species. Additionally, we concluded that M. liza has a wide distribution in the Atlantic coast of the South Caribbean and South America and that all specimens analyzed of this species belong to a single population. © Taylor and Francis Group, LLC.