Nanocrystalline dense sub-micron thin films of Ce0.8Gd0.2O2-delta have been successfully deposited by flame spray deposition. The deposition mechanism has been identified as droplet deposition. The deposition temperature of the substrate was as low as 200 degrees C and the deposition rate similar to 30 nm/min. Under these conditions the droplets have a very limited residence time in the hot zone of the flame and are deposited as liquid, forming smooth films free of particles. They exhibited a dense and crack-free microstructure. Grain growth, lattice constant, crystallographic density and surface roughness have been investigated as a function of annealing temperature. The good quality of the films, in association with the high deposition rates at low deposition temperatures shows the preeminence of the flame spray method for depositing thin films for micro-solid oxide fuel cells. (C) 2010 Published by Elsevier B.V.