DNA barcoding regions have been used for identifying organisms and delimiting species. Our research focused on butterflies belonging to the Enantia jethys species complex (Lepidoptera: Pieridae) in Mexico, specifically to resolve the taxonomic problem of the number of species in the group. We used the standard segment of approximately 650 base pairs of the mitochondrial cytochrome oxidase subunit I (COI) gene. Our study is the first to use DNA sequences to examine phylogenetic relationships of this complex species. Three phylogenetic inference methods used were parsimony, maximum likelihood, and Bayesian inference. Twospecies delimitation methods also were used: generalized mixed Yule-coalescent and Poisson tree process (bPTP). We used all the analyses to obtain 155 COI sequences and a persistent clade with four monophyletic groups: three corresponding to Enantia albania (Bates), Enantia jethys (Boisduval), and Enantia mazai Llorente, and a fourth corresponding to a new potential cryptic species, which must be described.