Flame pyrolysis has been used for many years in the fabrication of simple materials such as carbon black and fumed silica and is being used in the fabrication of many more compounds. Flame spray pyrolysis is of great potential for mass production of nano-materials, especially oxides and supported metals. Flames offer a unique environment for nano-particle growth since they contain high degrees of super-saturation, extremely high temperatures and rapid quench conditions and locking in kinetic structures. Spray jets flames offer the most versatile and controllable pyrolytic conditions for nano-particle formation. Flame spray pyrolysis processes are quite attractive as they can employ a wide array of precursor compared to conventional vapor-fed flame reactors. Each droplet contains the precursor in the same stoichiometry as desired in the product so a broad spectrum of functional metal and mixed metal oxide nanoparticles can be synthesized for catalysis, sensors and electroceramics. Nanoparticles of ZnO, MgO and NiO can be produced from droplets of aqueous salt solution in the flame spray pyrolysis reactor. Conventional spray pyrolysis in which electrical furnace reactor is used is reported to produce nanoparticles only from acetate precursor. If the reactor pressure is low (at 60torr), nitrate salt precursor is also known to produce nanoparticles. At low flame temperature, nanoparticles are not formed and the particle morphology is similar to the morphology produced by the conventional spray pyrolysis. At high flame temperature, nanoparticles are formed, regardless of the salt type. Nanoparticles are formed at lower flame temperature from acetate salts than from nitrate salts. Few examples reported are cited below.