C60 and C70 polycrystalline thin films, prepared by sublimation of powders onto carbon holey film substrates held at temperatures Ts of 40 and 200 °C, were investigated at room temperature using conventional and high resolution TEM. A strong dependence of grain size on Ts is observed. We obtain a mean grain size ˜25 nm for both C60 and C70 films when using Ts = 40 °C, but this size is ˜250 nm for C60 and ˜130 nm for C70 when using Ts = 200 °C. In all cases, however, an fc.c. structure with a high density of planar defecTs, twins and stacking faulTs, is observed. When a C60 film grown at Ts = 40 °C was annealed for several hours at only about 250 °C in vacuum, recrystallization took place, with grains as large as 250 nm now being present in the film. A condition to observe this recrystallization seems to be that the powder used to grow the film must be dried for long enough periods of time to minimize the amount of solvent residues.