We developed a rapid and convenient extraction procedure of human hair proteins to examine their biochemical properties in detail. This procedure is based upon the fact that the combination of thiourea and urea in the presence of a reductant can effectively remove proteins from the cortex part of human hair. The extracted fraction mainly consisted of hard α-keratins with molecular masses of 40—60 kDa, matrix proteins with 12—18 kDa, and minor components with 110—115 kDa and 125—135 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein phosphorylation in human hair was investigated by immunoblotting with antibodies against phosphoserine, phosphothreonine and phosphotyrosine. We found serine phosphorylation in α-keratins and matrix proteins and threonine phosphorylation in α-keratins. The extraction was also found to be effective when wool, chicken feathers, rat hair and human nails were used as starting materials.