Abstract: Kinetics of oxidation of maleic acid by N-chlorosuccinimide (NCS) in the presence of acidic solution of iridium (III) chloride as catalyst are presented. A perusal of results shows that first order kinetics in lower concentration range of NCS tends to follow zero-order kinetics at its higher concentration range. The reaction rate increases with increases in [Ir (III)] but order in [Ir (III)] in less than unity. Zero order dependence of the reaction on [maleic acid], [H+] and [succinimide] was observed. Initial addition of Cl- ion and five fold increases in ionic strength of the medium indicate negative effect of [Cl- ] ion and negligible effect of ionic strength on the reaction rate. Activation parameters have been calculated and reported.The mechanistic steps conforming to the observed kinetic result are proposed.