Bulk nanostructured Co90Ag10 immiscible alloys with Ag particle size of 10 nm have been fabricated by a combination of high energy ball milling and warm pressing. The Ag particle size increased to be 58 nm after annealing at 900 degrees C for 1 h. Pin-on-disk dry sliding wear tests show that even with over 20% hardness reduction, the annealed sample has similar wear resistance with the as pressed one. Wear induced strain in Co-Ag immiscible alloys could not force the formation of self-organized nanolayered structure or a supersaturated solid solution below the sliding surface. Electrochemical polarization tests show that such nanostructured Co-Ag alloys have no passive behaviour in the artificial saliva solution (ASS) but with high corrosion current densities. Energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analysis show that the corrosion products are composed of insoluble cobalt (II) phosphate, cobalt hydroxide and silver chloride. Such corrosion behaviour in ASS suggests Co-Ag alloys are not suitable candidate for dental applications.