The stereochemical structure of two samples of poly(acrylic acid) (PAA) of different tacticities was studied by a combination of one- and two-dimensional (2D) C-13-H-1 nuclear magnetic resonance (n.m.r.) spectra. Lines in C-13 n.m.r. spectra of PAA solutions in D2O could be assigned to configurational triads (CH region) and hexads or hexad pairs (CH2 region). For analysis of the CH2 region, the application of the inverse HETCOR (heteronuclear correlation) (i.e. heteronuclear multiple-quantum coherence, HMQC) 2D C-13-H-1 n.m.r method was essential. Both for CH and for CH2 carbon resonances our assignment differs from those previously published in the literature. The studied PAA samples prepared by radical polymerization or by hydrolysis of poly(t-butyl acrylate) obtained by anionic polymerization obey Bernoullian statistics.