Trimethylsilylcellulose (TMSC) was prepared from commercial cellulose with a mixture of hexamethyldisilazane and chlorotrimethylsilane in the solvent system N,N-dimethylacetamideAithium chloride. The soluble, highly silylated polymer (degree --of substitution, DS 2.9) had a molar mass aW of 500 kg/mol and a molecular non-uniformity U = (Mw/Mn) -1 of 2.9. In order to investigate the prin,cipal suitability of a continuous polymer fractionation for polysaccharides like cellulose derivatives and to obtain TMSC with different molecular weights and lower non-uniformity TMSC was fractionated by mearts of CPF (Continuous Polymer Fractionation), well-established in the field of synthetic polymers. The samples were fractionated using a mixed solvent, composed of toluene and dimethyl sulfoxide, and characterized by capillary viscometry, gel permeation chromatography (GPC), and GPC-light scattering coupling. The molar masses of the fractions range from 110 to 600 kg/mol and their U values vary between 0.9 and 1.9. The intrinsic viscosities of TMSC in tetrahydrofuran at 25 "C and M, are related by [v] = K -M& where K = 0.0089 d g and a = 0.82.