ABSTRACT Since the mid-eighth century, Shosoin textiles have been continuously handed down in the Shosoin treasure repository of the Todaiji temple, Japan, and the brilliant colors of these ancient textiles have been maintained in good condition thus far. In this study, the chemical stabilities of madders (Rubia akane and R. tinctorum), gromwell (Lithospermum erythrorhizon), and blue indigo dyes remaining in the textiles passed down for more than 1250 years were examined. The dye components remaining in the silk or wool textiles were analyzed by high-performance liquid chromatography equipped with a photodiode array detector. Chromatograms of the extracts from the textiles revealed not only the principal chromophores of the dyes but also 6-hydroxyrubiadin glycosides and shikonin esters in Japanese madder and gromwell, respectively. These results indicated that the chromophore skeletons, glycoside linkages, and ester linkages of the dye components were retained for more than 1250 years after the textiles were stored in the treasure repository. These findings of the chemical stability and the ongoing degradation of ancient natural dyes help in preserving the dye components and slowing down their degradation.