Hydrogen behaviour in martensitic F82H steel was studied by internal friction. A broad internal friction peak was found in the temperature range of 100-450 K. It was shown that the peak consists of one relaxation component and two components corresponding to the transient processes of the hydrogen redistribution and outgassing. The relaxation component of the peak is caused by the Snoek-like process of the transition of hydrogen atoms between the tetrahedral interstitial sites coordinated with one and/or two chromium atom nearest neighbours. The binding energy of hydrogen to the lattice traps is 33 kj/mol. Cold working was shown to increase the hydrogen absorption capability of the material significantly by production of additional hydrogen traps.