Free radical polymerization of acrylonitrile (AN) is efficiently, easily, and quickly achieved in the presence of Co(III) complex, [Co(III) en(3)]Cl-3 and ammonium persulphate (APS) in domestic microwave oven. The rate of polymerization depends on the power and time of microwave irradiation, and is independent of the technique employed (periodic or continuous irradiation). The conversion of monomer to the polymer was mostly excellent in gram scale. Irradiation at low power and time produced more homogeneous polymers with high molecular weight and low polydispersity when compared with the polymer formed by conventional heating method. The interaction of reacting components was monitored by UV-visible spectrometer. The average molecular weight was derived by GPC and viscosity methods and sound velocity by ultrasonic interferometer. The uniform and reduced molecular size was characterized by transmission electron microscopy, the diameter of PAN particles being in the range 220-250 nm in microwave and 120-530 nm in conventional heating methods. From the kinetic results, the rate of polymerization (R-p) was expressed as R-p = K[Co(III)](0.33)[APS](0.31)[AN](0.88) (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 1837-1842, 2010