Two metastable β-Ti alloys were subjected to high pressure torsion. Microstructure fragmentation increases with increasing strain. Twinning system {1 1 2} <111> is active during deformation by high pressure torsion. Hardenability exponent for both studied alloys is higher than for Ti-6Al-4V alloy. Young's modulus first increases due to high pressure torsion and then decreases with increasing strain.