In previous paper, synthesis of vitamin D_2 tetraacetylglucoside was reported. The present work was concerned with the stability of this derivative under various storage conditions. Crystalline vitamin D_2 tetraacetylglucoside (D_2 TAG) were sealed in glass ampules in the presence of either air or nitrogen gas, and then stored for 175 days in a freezer (-20℃), incubator (40℃), or a room under either dark or light (avoid direct sunlight). Observations on coloring of the crystals, determinations of melting points, developments by thin-layer chromatography, measurements of UV-and IR-absorption spectra and column chromatographic analyses were carried through the storage period. Vitamin D_1 stored under the identical condition was examined as controls. From these results, it was found that vitamin D_2 TAG was more stable than vitamin D_2.