Benzoylation of benzyl β-l-arabinopyranoside with 2.2 molar equivalents of benzoyl chloride gave benzyl 2,3-di-O-benzoyl-β-l-arabinopyranoside (65–70%) and benzyl 2,3,4-tri-O-benzoyl-β-l-arabinopyranoside (10–15%). Benzyl α-d-xylopyranoside, under similar conditions, gave benzyl 2,4-di-O-benzoyl-α-d-xylopyranoside (45%), benzyl 2,3-di-O-benzoyl-α-d-xylopyranoside (27%), benzyl 2,3,4-tri-O-benzoyl-α-d-xylopyranoside (15%), and benzyl 2-O-benzoyl-α-d-xylopyranoside (9%). Several new derivatives of benzyl β-l-arabinopyranoside and benzyl α-d-xylopyranoside have been prepared. These benzoates lead to the ready preparation of 4-O-substituted l-arabinose and d-xylose derivatives. These results are compared with those obtained for the selective benzoylation of hexopyranosides.