The aim of this work is to investigate the usage of rice husk ash in improving the properties of Portland cement which used in solidification of radioactive waste. Untreated and potassium Hydroxide (KOH)-treated rice husk ash loaded with Cobalt, Strontium and Cesium were fixed on ordinary Portland cement. In the present study, Cobalt, Strontium and Cesium ions were used instead of Cobalt, Strontium and Cesium isotopes because the chemical behavior of the metal ions is similar to radioisotopes. Mechanical properties, effect of temperature on the compressive strength and leaching behavior of the final solid waste block had been studied. The results obtained showed that the compressive strength increases by an increasing amount of additives added for untreated rice husk ash, but decreases for KOH treated rice husk ash blocks. Infrared analysis (IR) and Thermogravimetric analysis (TGA) were performed. Effect of contact time and initial concentration on the leaching process using distilled water and underground water as leachants had been investigated. The results showed the effective use of ordinary Portland cement in solidifying and stabilizing radioactive waste and using rice husk ash as substitution cementing material is effective in enhancing the properties of cemented radioactive waste matrices.