The kinetic behaviour of living isobutylene polymerization initiated by TMPCl/TiCl4 at -80 degrees C in Hx/MeCl solvent mixture was simulated using the PREDICI(R) polymerization simulation software. The basis of the simulation was the newly developed comprehensive mechanistic scheme, involving a series of consecutive and competitive reactions. This scheme accounts for the interesting phenomenon that living isobutylene polymerization may display either first or second order dependence on [TiCl4](0), depending on reaction conditions. The complex mechanism of the system was simplified and the kinetics was described using composite rate constants. The simulation results showed good agreement with experimental data.