The cat flea, Ctenocephalides felis, and the human flea, Pulex irritans, are species of significant human and veterinary health concerns. Genetic analysis of these species may provide insight into the dispersal of these insects and the spread of insecticide resistance. For this study, a total of 58 fleas were collected from Texas and Arkansas from both dwellings and pet animals. A total of 52 fleas collected were identified as C. felis, and 6 were identified as P. irritans. Samples were subjected to PCR and DNA sequencing using two markers, a portion of the mitochondrial DNA 16S rRNA gene and the nuclear rRNA first internal transcribed spacer region. For both species, no genetic variation was observed in either the nuclear or mitochondrial markers. Based on this observed lack of genetic variation, C. felis and P. irritans possibly underwent a genetic bottleneck in the United States.