An extremely high enantioselectivity of cellulose tris(3,5-dichlorophenylcarbamate) was found when it was used as a chiral stationary phase (CSP) in high-performance liquid chromatography (HPLC). The enantioseparation factor (alpha = 112) reported in this system for 2-(benzylsulfinyl)benzamide seems to be the highest among many enantiomer-differentiating separations using polysaccharide derivatives as CSPs.