Zirconium molybdosilicate (ZrMoSi) gel prepared using 99 Mo radiotracer via peroxo route was used as a base material for 99 Mo/ 99m Tc column generator. The 99m Tc elution yield and 99 Mo breakthrough in the eluate were studied as a function of the pH-value of gel precipitation, gel drying temperature and Zr : Mo : Si molar ratio. Precipitation pH-value of 2, drying temperature of 100 ∘ C and Zr : Mo : Si molar ratio of 0.5 : 0.5 : 1 were found to be the optimum conditions achieving 99m Tc elution yield of 82% and 99 Mo breakthrough of 1.0 × 10 −3 %.The gel prepared with the optimum conditions was characterized by BET surface area and pore size analyzer, IR spectroscopy, thermal analysis (TGA and DTA), XRD, XRF and FESEM. Technetium-99m eluted from the optimum ZrMoSi 99 Mo/ 99m Tc generator was found to have a high radiochemical purity (98% as 99m TcO − 4 ) and chemical purity meeting criteria of clinical grade.