Glycoproteins recognized by Ulex europaeus lectin I, specific for fucose residues, have been identified in chromatin prepared from pig liver, heart and kidney nuclei. They are present among the proteins dissociated from DNA with salt solutions and, in higher amount, among the proteins dissociated with urea and guanidine. In any case these fucose-containing glycoproteins appear to have a marked tissue specificity, which suggests that they have specific regulatory roles in the processes taking place in the nuclei.