Experimental EPR studies of the properties of more than 200 melanoprotein samples from human hair were conducted. The EPR signal from keratin associates was found for the first time. Conclusions were drawn from the temperature dependences of the keratin signal parameters concerning the structural states of the protein polymer: melting, glass transition, dehydration. Arguments in support of localization of paramagnetic centers on the surface of bound keratin tetramers are presented. The temperature evolution of the parameters of the EPR signal of melanin was investigated. It was shown that the material of pigment granules corresponds to a small organic semiconductor with E similar to 0.15 eV.