The mechanical deformability of RBC membranes could be measured at subzero temperatures using the technique described in part I of this paper. The results show a rapid increase in the elastic modulus with decreasing temperature. Substitution of glycerol in cryoprotective concentration has no influence on the mechanical behaviour. At nearly -20.degree. C the deformability of erythrocytes is zero. These experiments demonstrate that RBC membranes are nearly brittle in the temperature range of ice formation in a cryoprotective solution.