Treatments of wool with either formic acid or 50per thousand aqueous propanol are known to increase abrasion resistance. The proteins extracted by these treatments have been characterized by amino acid analysis and polyacrylamide gel electrophoresis in urea at pH 2.6 and 8.9, and in sodium dodecyl sulfate (SDS). SDS electrophoretic mobilities of the proteins indicated that they have molecular weights below 10,000. The proteins solubilized by propanol contained large amounts of glycine, the aromatic amino acids (tyrosine and phenylalanine), and serine, and a moderate amount of half-cystine. They are shown to be Type I high-tyrosine proteins, possibly derived from the matrix of the cortex. On the other hand, the fraction extracted with formic acid contained virtually no half-cystine and a large amount of glutamic acid, as well as glycine, serine, and the aromatic amino acids, and possibly originated in the cell membrane complex.