Dysprosium titanate (Dy2TiO5) based ceramic is one of the control rod materials for thermal reactors. This ceramic has been prepared by conventional mixing and calcination technique. The formation of DY2TiO5 phase from the DY2O3-TiO2 starting mixture has been found to be a two-step process. In the first step, the formation of dysprosium dititanate (DY2Ti2O7) phase takes place at 700 degrees C. This Dy2Ti2O7 reacts at around 1100 degrees C with remaining Dy2O3 present in the mixture to form DY2TiO5. The Dy2TiO5 phase has three polymorphs (orthorhombic, hexagonal, and fluorite). The fluorite phase is reported to have lowest in-service irradiation swelling characteristics when used as control rod elements in thermal reactors. In the present investigation, the fluorite polymorph of Dy2TiO5 has been stabilized by doping with molybdenum trioxide.