The solubility of CO2 in liquid water inside the stability field of CO2-hydrate is determined experimentally. Equilibrium between liquid and hydrate phases is achieved in a porous medium to ensure that the stable phases are isolated from the vapor phase (which is used to maintain pressure). Changes in the solubility with temperature are monitored using measurements of electrical resistance. The experiments indicate that the solubility decreases as temperature is lowered into the stability field of CO2-hydrate.