The release of water, which is essential for collagen's biophysical properties [5,19–21], results in a decrease in electrical conductivity σ. Water release is a complex process, because water molecules participate in the structure of collagen macromolecule in different ways. In the solid state collagen, water is usually divided into three groups: free water, bound water and structural water [6]. The process of water release from fish skin collagen was studied by means of dc electrical conductivity measurements carried out in the temperature range 290–510 K and the heating rate 2 K/min. The process of free and bound water release was manifested as a peak on the electrical conductivity-temperature curve between 320–350 K. Further increase in the temperature resulted in an increased electrical conductivity.