The kinetics of phase transfer catalysed free radical polymerisation of butyl methacrylate using potassium peroxydisulphate as water soluble initiator and propiophenonebenzyldimethylammonium chloride (PPBDAC) as phase transfer catalyst were studied. ne polymerisation reactions were carried out in cyclohexanone-water biphase media at 60 degreesC in an inert atmosphere under unstirred condition. The effect of various experimental conditions such as different concentrations of monomer, initiator, phase transfer catalyst (PTC) and different ionic strength, temperature and the volume fraction of aqueous phase is studied. The order with respect to monomer, initiator and the phase transfer catalyst is found to be 1, 0.5 and 0.5 respectively. The rate of polymerisation (R-p) is independent of ionic strength and pH. However, an increase in the polarity of solvent and volume fraction of aqueous phase slightly increases the R-p value. Based on the results obtained, a mechanism has been proposed for the polymerisation reaction.