The polymerization of o-(1,3-dioxolan-2-yl)phenyl ethyl fumarate (DOPEF) initiated with dimethyl 2,2＇-azobisiso-butyrate (MAIB) was studied kinetically in benzene. The polymerization rate (R-p) at 60 degrees C was given by R-p = k [MAIB](0.76)[DOPEF](0.71). The overall activation energy of polymerization was calculated to be 98.3 kJ/mol. The number-average molecular weight of resulting poly(DOPEF) was in the range of 1000-3100. H-1- and C-13-NMR spectra of resulting polymers revealed that the radical polymerization of DOPEF proceeds in a complicated manner involving vinyl addition, intramolecular hydrogen abstraction, and further ring opening of the cyclic acetal at higher temperatures. From the copolymerization of DOPEF (M-1) and styrene (St) (M-2) at 60 degrees C, the monomer reactivity ratios were obtained to be r(1) = 0.02 and r(2) = 0.20, the values of which are similar to those of the copolymerization of ethyl o-formylphenyl fumarate and St.