Nucleotide sequence variation in cytochrome oxidase I genes of the mitochondrial genome were sequenced in 17 Speyeria Scudder species. Phylogenetic hypotheses of DNA sequences were constructed by utilizing PAUP via maximum parsimony analysis. Sequences generated by four related taxa (two North American and two European) were used as outgroups to root the trees. This preliminary analysis comprises a portion of an in-depth study on the evolution of genes and species within Speyeria butterflies. The overall study represents the first attempt to provide a detailed molecular overview of all of the species in this taxonomically challenging genus as well as all members of the Speyeria atlantis/hesperis complex.