This study was performed to investigate the applicability of the theory of capillary condensation of moisture in fractal nanopores of native cellulose powders of various origins. The characteristic fractal dimensions D were calculated and their physical meaning discussed. The method proved useful for obtaining versatile information about the water-cellulose interactions as well as the bulk structure of cellulose particles. (C) 2004 Elsevier B.V. All rights reserved.