The creep properties for the Hastelloy-X alloy which is one of candidate alloys for a high temperature gas-cooled reactor are presented. The creep data was obtained with different stresses at 950oC, and a number of the creep data was collected through literature surveys. All of the creep data were combined together to obtain the creep constants and to predict a long-term creep life. In the Norton’s creep law and the Monkman-Grant relationship, the creep constants, A, n, m, and m’ were obtained. Creep master curves based on the Larson-Miller parameter were presented for the standard deviations of 1σ, 2σ and 3σ. Creep life at each temperature was predicted for a longer-time rupture above 105 hours. Failure probability was also estimated by a statistical process of all the creep rupture data.