Complex ring C-13 resonance lines of the cross-polarization/magic angle spinning (CP/MAS) C-13 NMR spectra of cellulose triacetate (CTA) I and CTA II were completely assigned, for the first time, by C-13-enriched CTA allomorphs. The C-13-enriched CTA I was prepared by heterogeneous acetylation of bacterial cellulose which was biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 from culture medium containing D-(2-C-13)-, D-(3-C-13)-, or D-(5-C-13)glucose as a carbon source, while CTA II samples were obtained by solution acetylation of the C-13-enriched bacterial celluloses. From comparison of the spectra of normal CTA prepared from ramie with those of the enriched CTA samples, it was revealed that all carbons composed of CTA I appeared as a singlet, while those of CTA II except for Cl were shown as equal-intensity doublets in the CP/MAS C-13 NMR spectrum. This finding suggests that CTA I is made up of one kind of glucopyranose residue while there are two magnetically inequivalent sites in the unit cell of CTA II in the same population.