The solubility of carbon dioxide in pure water in the presence of CO2 gas hydrate has been measured at temperatures between 273 and 284 K and pressures ranging from 20 to 60 bar. It was found that the solubility decreases with decreasing temperature in the hydrate formation region. In the absence of gas hydrate, the gas solubility increases with decreasing temperature, but the hydrate formation process changes this trend. This confirms theoretical calculations as well as removes previously reported ambiguities. It was also observed that pressure was not a strong factor on the solubility.