Ni-B coatings have been deposited directly on commercial purity magnesium and evaluated by means of sliding wear and friction testing. The nickel and boron are distributed throughout the whole thickness of the coating. Parametric optimization has been carried out using design of experiment based on Taguchi analysis. The friction coefficients of the coatings vary between 0.01-0.3, depending of the evaluated conditions. The lowest wear rate of the coating was 0.19 × 10-5 mm3 N-1 m-1. Wear and friction coefficient maps of Ni-B electroless coatings formed on magnesium surfaces are reported. Nanoparticles present in the lubricating fluid acts as a third wear body increasing the wear of the electroless coating.