Vinyl acetate and maleic anhydride are known to give 1:1 radical alternating copolymerization regardless of the monomer feed composition. The mechanism of this copolymerization involves free monomers and a complex between them (charge transfer complex). We undertook a study of the microstructure of different alternating copolymers (bylH,13C NMR, and thermogravimetric analysis). Starting from the results obtained, we determined the influence of the participation of the complex on the microstructure of the alternating copolymers.