Space treatments require droplets to remain air-borne for as long as possible, so it is usual to apply a fog. Fogging is particularly useful for the control of flying insects, especially mosquitoes, not only through contact with droplets but also by the fumigant effect of a volatile pesticide. This chapter discusses various types of thermal fogging machines such as pulsejet and large thermal fog generators. Cold foggers powered by an engine or a motor, are suitable for trolley mounting in glasshouses and warehouses, and for mounting on a flat-bed truck for mosquito control in urban areas. The chapter ends with a brief note on other types of fogging machines.