Zircon, ZrSiO4, is a prospective durable host material for the immobilization of excess weapons plutonium. Using cerium as a chemical analogue for plutonium, the experiments on the synthesis of Ce-doped zircon were conducted by sintering of sol-gel precursors in air and vacuum. The results showed that cerium substantially promotes zircon formation from sol-gel precursors and sintering in air is preferable for cerium incorporation in zircon structure. Based on measured lattice constants, solid solution compositions (Zr0.96Ce0.04)SiO4 and (Zr0.98Ce0.02)SiO4 were formed in samples sintered in air at 1400°C and 1600°C, respectively. The solubility limits of cerium and actinides in zircon and mechanism of zircon formation are discussed.