Mosquito nets provide a shield against mosquitoes and other insects. They also provide a shield against the diseases the insects may carry, including yellow fever, dengue fever, malaria, and different types of encephalitis (West Nile virus is an example of this.). The nets are frequently used in areas where malaria or other insect-borne diseases are common. In order to work properly, the mesh of the net must be thin and delicate enough to keep mosquitoes out without encumbering the flow of air or ability for humans to see out.

The effectiveness of the net can actually be significantly enhanced by treating it with mosquito repellent or an insecticide. Nets are considered twice as effective when they are treated with insecticide. Insecticide-treated nets are considerably more effective than using no net at all. To achieve maximum efficiency, the nets should be treated with insecticide every six months. The treated nets help kill and keep away unwanted mosquitoes.

The nets can be used in several ways—they can actually be built into tents, built into the windows and doors of tents, hung over beds, or hung from the ceiling. When the nets are hung from beds, rectangular-shaped nets enable room for sleeping without the fear of the net coming in contact with the skin, which could cause mosquitoes to bite through netting that has not been treated properly.

Mosquito nets were first used to prevent malaria in the 1980s.