The aim of this paper is to study the microstructures and hardness of silver alloys after internal oxidation process. The Ag-5Sn and Ag-5Cu alloys were prepared by melting and cast into ingots and then they were internal oxidized at the temperature range from 550 to 750°C, for 24 hours under oxidizing atmosphere by feeding oxygen gas with the pressure of 1 kg/cm2, gas flow rate 5 l/min and cooled in the furnace. The microstructures, Vickers microhardness and phase compositions were investigated. The results showed that the microstructures of the based metal revealed dendritic structure and they were transformed to equiaxed grains after internal oxidation. The internally oxidized layer of Ag-5Sn alloy is SnO2 with the hardness about 106-133 HV. The internally oxidized layer of Ag-5Cu alloy is CuO with the hardness about 65-73 HV.