Dielectric constant and loss of frog nerve was determined at 6.3 GHz frequency and 20-50 degrees C temperature by a microwave cavity resonator measuring method developed by us. As a result of temperature denaturation the dielectric constant of frog nerve decreases, while its dielectric loss increases. According to our measurements the volume of bound water in nerve is approximately 0.44 ml/l ml dry material. The activation energy of water in the nerve is 16.8 kJ/mol.