Kinetics of oxidation of L-poline by N-bromosuccinimide (NBS) in aqueous acidic medium and water-alcohol, solvent mixtures were performed. The reaction was first order dependent on both [proline] and [NBS]. The rate of reaction was inversely dependent upon [H+] through the pH range 2.6-3.3 and varied with the cosolvent according to the order MeOH > EtOH. The conjugate base of amino acid was considered as the main reactive species. An inner-sphere mechanism in which the conjugate. base of amino acid Was attached by,NBS to form the precursor intermediate complex was proposed.