  We have observed room temperature ferromagnetism (FM) in In$_2$O$_3$ thin
films doped with either 5 at.% Mn or Fe, prepared by pulsed laser deposition
(PLD) at substrate temperatures ranging from 300 to 600$\,^{\circ}{\rm C}$. The
dependence of saturation magnetization on grain size was investigated for both
types of In$_2$O$_3$ films. It is revealed that, for the Mn-doped films, the
magnetization was largest with small grains, indicating the importance of grain
boundaries. In contrast, for Fe-doped films, the largest magnetization was
observed with large grains.
