This study was carried out to investigate the physical and thermal properties of κ-carrageenan (κ-car) gel added wheyprotein isolate (WPI) as a cryoprotectant. The concentration of κ-carrageenan was fixed at 0.2 wt%. The mean ice crystalsize of the WPI/ κ-car was decreased according to increasing whey protein isolate concentration. The temperature of gel-sol(Tg-s) and sol-gel (Ts-g) transition of WPI/ κ-car maxtrix was represented in the order of 3.0, 0.2, 5.0 and 1.0 wt%. In addi-tion, the transition temperature of gel-sol of WPI in sucrose solution were showed in order of 1.0, 5.0, 0.2 and 3.0 wt%depending on whey protein isolate concentration. The shape of ice crystal was divided largely into two types, round andrectangular form. 1.0 wt% WPI/κ-car matrix at pH 7 and 9 showed minute and rectangular formation of ice crystals andwhey protein isolate in sucrose solution at a concentration of 1.0 wt% WPI/κ-car matrix at pH 3 and 5 showed relativelylarge size and round ice crystals. The ice recrystallization characteristics and cryprotective effect of κ-carrageenan changedthrough the addition of different concentrations of whey protein isolate. It seems that the conformational changes inducedinteractions between whey protein isolate and κ-carrageenan affected ice recrystallization.Key words: cryoprotectant, ice recrystallization, κ-carrageenan, whey protein isolate