The effect of fullerene (C-60) on the radical polymerization of vinyl acetate (VAc) with dimethyl 2,2'-azobisisobutyrate (MAIB) in benzene was investigated kinetically and by means of ESR. C-60 was found to act as an effective inhibitor in the present polymerization. All C-60 molecules used were incorporated into poly(VAc) during polymerization. The relationship of induction period and initiation rate reveals that a C-60 molecule can trap 15 radicals formed in the polymerization system. The polymerization rate (R-p) after the induction period is given by R-p = k [MAIB](0.6) [VAc](2.0) (60 degrees C), which is similar to that observed in the absence of C-60. Stable fullerene radical (C-60. ) was observed in the polymerization system by ESR. The C-60. concentration increased with time and was then saturated. The saturation time well corresponds to the induction period observed in the polymerization. About. 20% of C-60 molecules added could survive as stable C-60..