A metal ebulliometer has been used to measure the solubility of water in 2,2-dichloro-1,1,1-trifluoroethane (HCFC 123) over the temperature range 297-354 K. Solubilities varied from 9.5 x 10(-3) to 3.75 x 10(-2) (mole fraction). Activity coefficients (gamma (infinity)) and distribution coefficients (KW) were estimated. The results were used to resolve a discrepancy found in the literature concerning the vapor pressure of HCFC 123.