The polymerization of acrylonitrile (M) initiated by the sorbitol (R)-Ce(IV) redox system has been studied in sulphuric acid in the range 30–40° under nitrogen. At moderately high concentrations of Ce(IV) (0.00015-0.02 M), the rate of polymerization (Rp) is proportional to and and the rate of Ce(IV) disappearance is proportional to [R] and [Ce(IV)]. At lower concentration of Ce(IV) (0.00005–0.00015 M) Rp is proportional to [M], [R]1/2 and [Ce(IV)]1/2 and rate of Ce(IV) disappearance is proportional to [R] and [Ce(IV)]. The effects of certain salts, acid, solvent and temperature on both rates have been investigated. A kinetic scheme involving mutual termination has been proposed and various rate and energy parameters evaluated. At still higher concentration of Ce(IV) (0.02 M), a linear mode of termination seems to operate.