The kinetics of oxidation of mannitol by cerium(IV) in sulphuric acid medium have been studied. The spectral analysis of hydrazone derivative of the product indicates the product to be an aldehyde. The substrate forms an intermediate complex with the oxidant as is observed both kinetically and spectrophotometrically. Ce(SO4)2 has been considered to be the reactive sulphato-cerium(IV) species. The proposed mechanism corresponds to the rate law−d[Ce(IV)]dt=2kK[RCH2OH][Ce(IV)](1+K[RCH2OH])(1+K3[HSO4−])where R=CH2OH(CHOH)4. All the rate parameters have been evaluated.