Indium(III) hydroxide nanopowder has been successfully obtained by hydrolysis of indium chloride in alkaline alcohol solutions. Its suspension has been used to form thick films of In2O3using a drop-coating method with a following thermal decomposition of indium hydroxide upon the glass substrate. Concentrations of precursors have been varied to influence well a particle size in colloids. The same synthesis has been applied to form In2O3inverse opals by impregnation of polystyrene opals with an ethanol suspension of In(OH)3nanopowder of the finest particles. Phase composition, temperature of decomposition and micromorphology of the samples have been investigated by X-ray phase analysis, dynamic light scattering, thermal analysis, transmission and scanning electron microscopies.