The Dermanyssoidea is an extremely diverse lineage of mites that are found as free-living predators as well as facultative and obligate parasites of mammals, birds, lepidosaurs, and various arthropod groups. The primitive condition in the group is assumed to be that of free-living predators, and parasitism is thought to have evolved numerous times throughout Dermanyssoidea. In non-phylogenetic treatments, the subfamily Hypoaspidinae (Laelapidae) has been hypothesized as the most primitive group within Dermanyssoidea, and the subfamily Laelapinae has been was suggested as the source of most parasitic lineages. This study uses the 28S region (domains 1-3) of the nuclear rDNA array to address phylogenetic relationships within Dermanyssoidea and the evolution of parasitism. Results suggest parasitism of vertebrates and arthropods has evolved a minimum of eight independent times, and the majority of these events have occurred outside of the Laelapinae.