Pure Hf (99.99%) is processed by high-pressure torsion (HPT) under pressures of 4 and 30GPa to form an ultrafine-grained structure with a gain size of ∼180nm. X-ray diffraction analysis shows that, unlike Ti and Zr, no ω phase formation is detected after HPT processing even under a pressure of 30GPa. A hydride formation is detected after straining at the pressure of 4GPa. The hydride phase decomposes either by application of a higher pressure as 30GPa or by unloading for prolong time after HPT processing. Microhardness, tensile and bending tests show that a high hardness (360Hv) and an appreciable ductility (8%) as well as high tensile and bending strength (1.15 and 2.75GPa, respectively) are achieved following the high-pressure torsion.