The states of water in gel cellophane membranes were investigated by DSC measurements. An extra exothermic peak, which has not previously been reported, was observed at heating rates slower than 2.5K/min. The peak was ascribed to the crystallization of the liquid water in the heating process. The ratio of the nonfreezing water (often referred to as bound water) (g) to the dry membrane (g) was estimated to be 1.06. This value is far larger than the bound water contents reported for cellulose acetate membranes (Frommer et al. 1972, Taniguchi et al. 1975).