Molecular chaperones in living systems inspired us to explore new concepts for assisting protein refolding. The chaperone selectively interacts with a non-native protein by hydrophobic interaction to prevent irreversible aggregation and releases the protein in its refolded form with the aid of ATP and another co-chaperone. Cyclodextrins have been used to simulate the function of the chaperones by controlling the hydrophobic interaction with proteins. In this chapter, we review the cyclodextrin (CD)-related protein refolding systems.