Investigation of parchment samples by means of x-ray fluorescence and combustion analysis in all cases reveals noticeable portions of sulfur. It therefore seems to be justified to take into consideration sulfur-bearing substituents as possible binding-sites for transition metal ions in the course of pigment-induced degradation of parchment. In order to clarify this question samples of decayed parchment as well as undamaged parchment of contemporary origin were analyzed with respect to their contents of sulfhydryland disulfide groups as well as sulfate stemming from acid glycosaminoglycans (GAGs) of the ground substance of connective tissue. Sulfate was estimated by turbidimetric measurement after separation of GAGs from the proteinaceous portion of parchment. Sulfhydryland disulfide groups were titrated amperometricaily after reductive treatment of the samples by sodium borohydride. It could be shown that sulfhydryland disulfide sulfurs without exception represent the main portion of sulfur in parchment, whereas sulfate from acid GAGs is present only in minimal amounts. See also AATA 17-1070, 18-1152, 20-1558, and 21-338.