This paper describes a successful dispersion catalytic chain transfer polymerization (CCTP) of methyl methacrylate (MMA) in the presence of a transition-metal catalyst (tetraphenylcobalt-oxime boron fluoride, COPhBF (I)) in supercritical carbon dioxide (scCO(2)) using poly(dimethylsiloxane) monomethacrylate (PDMS-ma) macromonomer as a stabilizer. The final product is a dry, fine powder with controlled molecular weight and a narrow molecular weight distribution. It was found that the dispersion polymerization could reduce the activity of CCT catalyst, which can lead to facile and controlled preparation of high molecular weight vinyl-terminated macromonomers.