Hydrogen solubility and diffusivity in HR-1 steel have been determined by a vacuum heating degassing technique at 597-1022 K on a set of specimens with different sizes previously charged for 24 h under a hydrogen pressure of 105 Pa in the temperature range of 800-1000 K. The permeability was then derived from the relation Φ = DKs. It is found that D = 1.52 × 10-6 exp(-54100/RT), Ks = 2.2× 10-6 exp(-5400/RT), and Φ = 3.3× 10-12 exp(-59500/RT) where Ks (Sieverts' constant) is given in Pa- 1/2 , D in m2s-1, Φ in m2s-1 Pa- 1/2 , T in K and R = 8.31 J g atoms-1 K-1.