The C-13 NMR spin-lattice relaxation times (T-1) of anhydroglucose units vary with the number of substituents, and the T-1 values of unsubstituted anhydroglucose units of O-carboxymethylcellulose are longer than those of amylose. Those results indicate that in water, the rotational motions of anhydroglucose units of cellulose derivative are quite important local motions contributing to the C-13 NMR spin-lattice relaxation, and within a cellulose chain, anhydroglucose units rotate with different degrees of freedom depending on their environment. Moreover, the C-13 NMR spin-lattice relaxation data indicate that the mobilities of ionic substituents are dependent on substitution positions as well as their ionic interaction.