The effect of saccharin on the reduction of crystallite size and nickel electroplating properties was investigated. There are some techniques to obtain nanocrystalline coating and to reduce crystallite size in electrodeposition such as current density, mode of electrodeposition, and organic additive, one of which is saccharin. This charges of 0, 0.5, 1.0, 5.0, 10â€ g/l saccharin, air agitation, current density 6 A/dm2, and with electrolyte solution generally used in nickel electroplating industry is Watts nickel solution. The crystallite size of nickel plating was examined by X-Ray Diffraction, coating thickness was examined by thickness meter, hardness of plating were examined by Vickers hardness, corrosion rate was examined by salt spray test, and adhesive strength was examined by heat and quench test. From the result, it was found that the lowest crystallite size was obtained at 35 nm (10 g/L saccharin), the highest hardness was obtained at 593 HV (10 g/L), the best corrosive level is obtained in grade 8 which is 0.1% (0, 5, 10 g/L saccharin) of the corroded area, and the best adhesive level is obtained no blister in the surface (0, 5, 10 g/L). The increasing number of saccharin given will lead to decreasing crystallite size of plating and corrosion rate, and also will lead to the increasing hardness and adhesive strength.