The codeposition behavior of submicron sized diamond with nickel from nickel electrolytes has been investigated. Electroplating of diamond dispersed nickel composites was carried out on a rotating disk electrode (RDE). The effects of current type and current density on the electrodeposited Ni-diamond composite coating were investigated. The effects of pH and surfactants on the composite coating were also investigated. The hardness of coating was measured with varying electroplating conditions. As diamond was incorporated into the coating, the hardness of coating as well as the wear resistance was improved. The surface morphologies of the Ni-diamond composite coatings were observed using FESEM.