The radical initiated aqueous “slurry” copolymerization of acrylonitrile and vinyl acetate has been investigated. High field 13C-NMR spectra have been recorded for samples prepared employing both batch and starve-fed (semi-continuous) techniques. Copolymer composition and A-centred triad fractions have been obtained from the NMR spectra for a range of different feed compositions and give terminal model reactivity ratios of rV and rA of 2.7 and 0.05, respectively. However, the penultimate model gives a superior fit to the experimental A-centred triad fraction data. A comparison is made with data obtained for the same system employing the spin-trapping technique in conjunction with ESR spectroscopy.