This chapter reviews the ecology, geographical distribution, life cycle, host range, and feeding and reproductive behaviour of some of the most important disease vectors such as Culex, Aedes, Anopheles, Glossina, Siphonaptera, mites, and ticks. Epidemiological data on the range of human diseases they transmit are summarized, which include arboviral infections, malaria, filariasis, African trypanosomiasis, plague, typhus, and tickborne diseases.