Hydrate phase equilibria have been measured for carbon dioxide + cyclic ethers + water in the temperature range of (270 to 290) K and in the pressure range of (0.2 to 4.7) MPa. Three cyclic ethers, THF, propylene oxide, and 1,4-dioxane, were selected at a mole fraction of 0.03. The stabilization effect of the mixed hydrate was found to be the highest for THF followed by propylene oxide, while no stabilization effect was observed for 1,4-dioxane in the studied temperature and pressure range. The mole fraction effect on hydrate phase equilibria has also been investigated for THF and propylene oxide in the range of x = (0.01 to 0.10).