Biting midges are insects in the family Ceratopogonidae which are blood-sucking pests of vertebrate animals and humans. They are known for being annoying pests and vectors of disease agents such as Oropouche fever in humans, bluetongue in sheep and cattle, epizootic hemorrhagic disease in deer, and African horse sickness. This chapter explores the biology and disease ecology of biting midges, particularly, Oropouche. Lastly, diagnosis, laboratory findings, treatment and prevention of Oropouche and its vectors are presented and discussed.