Oximes of arabinose, ribose and xylose have been prepared from each pentose and hydroxylamine in anhydrous ethanol. Free hydroxylamine prepared from its hydrochloride by neutralization with sodium ethoxide was added dropwise into a pentose solution. Water in the solvent and that formed during the reaction were removed by coevaporation with benzene. Arabinose and ribose gave crystalline oximes. Although crystallization could be also achieved with xylose oxime under the present reaction conditions, collected crystals melted into syrup when they were left stand at room temperature. The formation of pentose oximes was demonstrated by paper chromatography, elemental analysis and NMR spectrum measurement in hexadeuterodimethyl sulfoxide. NMR spectroscopy furnished the relative contents of syn and anti form in each oxime and some other interesting informations.