Cyclohexanone oxime was employed as an oxidant in combination with Vanadium (III) as a redox initiator system for the polymerization of AN and MMA. Kinetics were investigated in aqueous sulphuric acid medium and mechanisms for oxidation and polymerization were proposed. Michaelis–Menten kinetics were evident from the rates of oxidation with protonation of oxime being the noncompetitive complexation. A mechanism involving monomer in the initiating radical production step and mutual termination of growing radicals was proposed to account for the fractional orders in the initiator concentration and the monomer exponents higher than unity. Copyright © 1986 John Wiley & Sons, Inc.