The ionization constant values of Cerium Nitrate at temperatures 288, 293 & 298 Kelvin and at pH 6.3, 6.5 & 6.7 (K) were calculated with the help M.B. Kings equation. It was found from the data that the value of the ionization constant was highest at 298K and pH 6.3, while it was lowest at 288 (K) and pH 6.3. The extraction of Cerium Nitrate in aqueous phase was also affected with the change in pH. Since K was highest at pH 6.7, therefore it is advisable to extract Cerium Nitrate in aqueous phase at pH 6.7 instead of 6.3. The temperature has no significant effect but the concentration factor considerably affects the extraction process.