In order to prepare cellulose nanofibers, the electrospinning and subsequent deacetylation of cellulose acetate (CA) has been studied using various solvent systems. In this study, as a new solvent system for the electrospinning of CA nanofibers, a mixed solvent of acetic acid/water was developed. CA can be dissolved at acetic acid contents higher than 70 wt.%. Long uniform CA nanofibers with an average diameter of 180 nm were electrospun from a 17 wt.% CA solution in acetic acid/water(75/25). The average diameters of the CA nanofibers could be controlled from 160 nm to 1280 nm by changing the composition of the mixed solvent. The nonwoven mat structure of the CA fibers was well maintained during their deacetylation. (c) 2007 Elsevier B.V. All rights reserved.