Culicoides biting midges are economically-important vectors of livestock viruses (arboviruses) and medically-important vectors of human filarial or virus pathogens. In North America, Culicoides spp. transmit bluetongue and epizootic hemorrhagic disease viruses to domestic and wild ruminants. Studies of other arthropods suggest that vector saliva potentiates establishment of arbovirus infection in mammalian hosts, even in the absence of viremia. In addition to transmitting pathogens, midge biting activity may also cause other animal health problems. For example, Culicoides salivary allergens cause type I hypersensitivity in horses, known as sweet itch, and may cause similar responses in other animals, as well. In order to generate tools for future elucidation of these conditions, we generated a cDNA library from adult female salivary glands and performed single pass DNA sequencing. Conceptual translation of this expressed sequence tag collection revealed many putative pharmacologically-relevant proteins. Possible functional groups include allergens and immunomodulatory factors. One such group is a novel class of short D7-related proteins, a diverse class of proteins of unknown function belonging to the odorant/pheromone binding family. Another group comprises a new class of putative coagulation inhibitors bearing the Kunitz_BPTI protease inhibitor domain. The significance of this cDNA collection to future studies of virus/vector/host interactions will be described.