The purpose of this study is to reveal whether Coenzyme Q10 (CoQ10) forms pseudorotaxane-like supramolecular complex with gamma-cyclodextrin (gamma-CyD). The poorly soluble complex of CoQ10 with gamma-CyD in water was prepared by the solubility method. The X-ray diffraction pattern of the CoQ10/gamma-CyD complex was different from that of the physical mixture, but almost the same as that of polypropylene glycol (PPG)/gamma-CyD polypseudorotaxane. Also, the differential scanning calorimetrical study and FT-IR study demonstrated the interaction between CoQ10 and gamma-CyD in the solid state. The 1H-NMR study and the yield study of the supramolecular complex of CoQ10 with gamma-CyD demonstrated that the stoichiometry was 5 : 1 (gamma-CyD : CoQ10). The dispersion rate of CoQ10 was markedly increased by the formation of the supramolecular complex with gamma-CyD, possibly due to submicron-ordered particle formulation. In fact, CoQ10 was found to form submicron-sized supramolecular particles with gamma-CyD, when prepared by the solubility method. Consequently, the present study showed that CoQ10 forms the pseudorotaxane-like supramolecular complex with gamma-CyD in water.