Ag-doped BaTiO3 based X7R (temperature coefficient of capacitance within the range of 15% between -55 and + 125 degrees C) ceramics with different amounts of silver (0.0-20.0 mol%) were prepared in this paper. The X-ray diffraction analysis indicated that no phases other than BaTiO3 and silver were observed in the ceramics. The energy dispersive X-ray spectroscopy analysis showed that the silver particles presented homogeneous distribution in the BaTiO3 ceramics. The dielectric properties of Ag-doped ceramics were investigated. A small amount of silver (<0.5 mol%) and a large amount of silver (>2.0 mol%) could both improve the sintered density and permittivity, but more content of silver (0.5-2.0 mol%) would decrease the relative density and permittivity. Specially, the temperature coefficient of capacitors of the ceramics doped with 20 mol% silver still met the X7R characteristics. and the room temperature permittivity of the ceramics was 6823, which was the highest dielectric constant in the BaTiO3 based X7R ceramics. (C) 2008 Elsevier Ltd. All rights reserved.