The copolymerization reaction between 2-hydroxyethyl methacrylate and t-butyl acrylate in a 3 mol l(-1) N, N'-dimethylformamide solution at 50 degrees C, using 2,2'azobis(isobutyronitrile) as initiator was carried out and values of r(HEMA) = 1.792 and r(TBA) = 0.510 were found for the monomer reactivity ratios. High-resolution H-1 NMR spectra of copolymers have been analyzed in terms of sequence distribution and stereoregularity. The alpha-CH3 resonance region contains five resonating peaks due to its sensitivity to triad concentrations. From these signals, triad concentrations were determined and its comparison with those calculated from Bernouillian statistics confirms the obtained results.