This invention relates to an improved process for preparing silver catalysts useful for the vapor phase production of ethylene oxide from ethylene and oxygen. An inert support is impregnated with a solution of a catalytically effective amount of a silver containing compound, a promoting amount of an alkali metal containing compound, and a promoting amount of a transition metal containing compound. The impregnated support is calcined by heating at a temperature of from about 200°C to about 600°C to convert the silver in the silver containing compound to metallic silver and to decompose and remove substantially all organic materials. The heating is conducted under an atmosphere comprising a combination of an inert gas and from about 10 ppm to about 5% by volume of a gas of an oxygen containing oxidizing component.