A process is described for reducing the total acid number of a refinery feedstock. In one embodiment, refinery feedstock containing naphthenic acids is contacted with an effective amount of solid catalyst in the presence of an aqueous caustic base, wherein the caustic base is sodium hydroxide or potassium hydroxide, for a period of time sufficient to neutralize at least a portion of the naphthenic acids in the feedstock. Thereafter, the aqueous phase is separated from the neutralized refinery feedstock. In another embodiment catalyst is pretreated with a caustic base solution and contacted with refinery feedstock to reducing the total acid number.