We have successfully constructed a redox-responsible hydrogel system by combination of beta-cyclodextrin (beta-CD), dodecyl-modified poly(acrylic acid) [p(AA/ C-12)] and a redox-responsive guest, ferrocenecarboxylic acid (FCA). In the reduced state of FCA, the ternary mixture exhibited a gel-like behavior, whereas, in its oxidized state, the mixture exhibited a sol behavior.