Compositionally homogeneous indium tin oxide (ITO) ceramics with low porosity were obtained successfully by sintering hydrothermally prepared powders. The fabrication technique began with the preparation of microcrystalline, homogeneously tin-doped (5 wt%) indium oxyhydroxide powder, under hydrothermal conditions. Low-temperature (similar to 500 degreesC) calcination of the hydrothermally derived powder led to the formation of a substitutional-vacancy-type solid solution of In2Sn1-xO5-y, and further heating of this phase at temperatures of >1000 degreesC resulted in the formation of the tin-doped Indium oxide phase, which had the C-type rare-earth-oxide structure. The sintering of uniformly packed, calcined powder compacts at 1450 degreesC for 3 h in air resulted in low-porosity (similar to0.7%) ITO ceramics.