Preferential leaching of Sr from irradiated thorium may play an important role to facilitate the management of high level waste as well as provide a new route to recover valuable fission product ⁹⁰Sr which has potential applications as (a) compact heat source and (b) as parent radionuclide for ⁹⁰Y, used in therapeutic radiopharmaceuticals. In the present work, leaching of Sr from (Th,Sr)O₂ in nitric acid and perchloric acid medium has been investigated as a function of acidity as well as refluxation time. It was interesting to observe that quantitative leaching of Sr(II) is possible even at 0.01M HClO₄where leaching of Th is negligible (~0.01%). Leaching behavior of other metal ions, like Pd(II), Y(III), and Zr(IV), representing few major fission products was also investigated.