Chemically modified cellulose microbeads are useful as cosmetic materials. Cellulose microbeads as supports, prepared by a viscose-phase-separation method, are monodisperse and spherical. However, cellulose shows only slight hydrophilicity, even though it has three hydroxyl groups per pyranose ring, because cellulose possesses high crystallinity on account of the cellulose II structure derived from hydrogen bonds among the hydroxyl groups. To increase the hygroscopicity of cellulose microbeads, we have carboxylatec them with succinic and glutaric anhydrides. Their hygroscopicity increases with the addition of succinoyl and glutaroyl groups. Moreover, we have confirmed the increased hygroscopicity of microbeads with sodium salinization. We have investigated the decomposition of these hydrophilic cellulose microbeads in aqueous buffer solutions and have confirmed that succinoylated cellulose is more readily decomposed than glutaroylated cellulose microbeads in aqueous solutions. On the other hand, to increase the lipophilicity of cellulose microbeads, we have acylated them with acetic and hexanoic anhydrides. Hydrophobizing microbeads with hexanoyl groups provides an affinity to benzene but not to H2O. In contrast, hydrophobizing with acetyl groups provides affinity not only to benzene but also to H2O. © 2005 Wiley Periodicals, Inc.