The invention relates to a process for demetallating a petroleum stream by contacting a metals-containing petroleum feed in the presence of a base selected from Group IA and IIA hydroxides and carbonates and ammonium hydroxide and carbonates and mixtures thereof an oxygen containing gas and a phase transfer agent at a temperature of up to 180.degree. C. for a time sufficient to produce a treated petroleum feed having a decreased metals content. The invention provides a method for enhancing the value of petroleum feeds that traditionally have limited use in refineries due to their metals, e.g., Ni and V content.