A number of viruses have been shown to be transmitted by the airborne route. It is the ability of these viruses to retain their infectivity for living hosts which play a key role in their aerial dissemination. Data generated by a number of workers on the airborne survival of viruses varies considerably because laboratory techniques have not been standardized. About 5 yr ago we started studies on the airborne survival of a number of animal and human viruses. This paper describes the methodology developed to study the aerobiology of these viruses. These methods should be useful in the aerobiological work of other viruses.