Density-functional-theory (DFT) study on methanol oxidation by ferrate (FeO42-) in water is reviewed in this chapter. The oxidizing power of three species, non-protonated, monoprotonated, and diprotonated ferrates was evaluated by using the B3LYP-D method. The oxidizing power increases in the order non-protonated ferrate < monoprotonated ferrate < diprotonated ferrate. The reaction pathway is initiated by C-H bond activation, which is the rate-determining in the overall reaction. Kinetic aspects of the reaction are analyzed from calculated energy profiles and experimentally known pKa values. The pH dependence of this reaction in water is explained well in terms of a multi-oxidant scheme.