The Simulium jenningsi species-group (Diptera:Simuliidae) is currently represented by 22 species of black flies that inhabit eastern North America. A phylogenetic analysis was conducted using DNA fingerprints from nuclear and mitochondrial genes. Although the mitochondrial data were relatively unsuccessful at resolving relationships within the group, nuclear sequences provided more informative data and performed better. However, many relationships between members of the group remain to be clearly understood.