The embodiments of the invention cover a ceramic sputtering target comprising at least 85 wt. % of an (In4Sn3O12 phase, wherein the ceramic sputtering target has a density of greater than 7.0 g/cm3. A method of forming an ITO ceramic sputtering target is also described by combining 53 to 65 wt. % of In2O3 and 35 to 47 wt. % of SnO2 to form a first In2O3/SnO2 mixture; mixing and milling the In2O3/SnO2 mixture in the presence of water and a dispersing agent until a first slurry is formed, wherein the average particle size of the first slurry is between 0.3-0.7 μm and wherein the specific surface area is between 4-8.5 m2/g; drying the first slurry to form a powder; heat treating the powder at 1300 to 1500° C. to form a compound having an In4Sn3O12 phase; adding additional In2O3 and SnO2 to the compound having the In4Sn3O12 phase thereby forming an In—Sn—O-based mixture having an atomic In/Sn ratio of 1.33; forming the ITO ceramic sputtering target.