Cellulose can be depolymerized by thermo-mechanical treatment at high temperature using ethylene glycol as solvent. A fraction of the cellulose is solubilized and the solid residual fraction consists of highly ordered cellulose with very low degree of polymerization and exhibits very high accessibility to enzymatic attack. Chemical characterization by thermal and spectroscopic techniques has shown that no chemical degradation occurs during depolymerization even if structural reorganization has been observed. Comparison with cellulose depolymerization byaqueous acid hydrolysis processes has shown the superior characteristics of the solvolytic process. The latter yields depolymerized cellulosic residues with increased accessibility to cellulases hydrolysis whereas the acid hydrolysis process even at very mild conditions results in functional modifications of the depolymerized cellulosic residue.