A method for magnetite-deposition on AgI-SiO 2 core-shell (AgI/SiO 2) particles is proposed. A colloid solution of 1.0×10 -3 M AgI nanoparticles was prepared mixing silver perchlorate at 1.0×10 -3 M and potassium iodide at 2.0×10 -3 M at 5°C, and then adding -3- mercaptopropyltrimethoxysilane at 4.5×10 -5 M at 20°C. AgI/SiO 2 particles with an average size of 42.7±10.3 nm and a AgI core size of 23.5±5.8 nm were prepared using a Stöber method at 20°C in water/ethanol solution with 8.0×10 -3 M tetraethylorthosilicate and 1.1×10 -3 M NaOH in the presence of 1.0×10 -3 M AgI nanoparticles. Preparation of magnetite nanoparticle colloid solution was performed with a homogeneous precipitation method using 5.0 M urea aqueous solution and 1.0×10 -2 M iron chloride aqueous solution with Fe 2+/Fe 3+ molecular ratios of 1/0, 2/1, 1/2 and 0/1 in (50/50) (v/v) water/1-propanol solution at 80°C. Magnetite that revealed ferromagnetic property were produced using the ratios of 1/0, 2/1 and 1/2. Magnetite-deposition on the AgI/SiO 2 particles was performed preparing the magnetite by the homogeneous precipitation method using 1.0×10 -2 M iron chloride and 5.0 M urea in the presence of the AgI/SiO 2 particles ([AgI] = 2.0×10 -4 M). Tiny magnetite nanoparticles were deposited on the AgI/SiO 2 particle surface. The magnetite-deposited AgI/SiO 2 particles were ferromagnetic, and were drawn close to magnet. These results confirmed that the homogeneous precipitation method was suitable to magnetite-deposition.