The solubility of the noble gases Ar, He, Ne, Kr, and Xe in pure water was measured from 298 to 561??K. These data in turn were extrapolated to the critical point of water, thus providing a complete set of Henry's law constants from 274 to 647??K when combined with the existing literature data. Equations describing the behavior of the Henry's law constants over this temperature range are also given. The data do not confirm extrapolations of empirical correlations based on low-temperature solubility data. ?? 1978 Plenum Publishing Corporation.