Nanofibrillar carbons were prepared by the carbonization of prawn chitin and wood cellulose nanofibers. Chitin and cellulose nanofibers with the average width of 10 nm were obtained by a grinder treatment from prawn shells and wood cell walls, respectively. Nanofiber aerogels prepared from nanofiber-water suspensions by solvent exchange and freeze-drying were used as carbon precursors. Since chum nanofibers did not flocculate in organic solvents due to their low hydrophilicity, the aerogels of chitin nanofibers did not form wide bundles of coalesced nanofibers. Furthermore, chitin nanofibers had higher thermal stability than wood cellulose nanofibers. Thus, after the carbonization of chitin nanofibers, the original fine and individual nanofiber network was maintained in the chitin carbon. In contrast, after the carbonization of wood cellulose nanofibers, the original nanofiber morphology was destroyed due to the aggregations of wood cellulose nanofibers and their low thermal stability. (C) 2010 Elsevier Ltd. All rights reserved.