Methods of intensive plastic deformation such as equal-channel angular pressing and versatile forging (abcpressing) [1–3] have been used most widely for the formation of the submicrocrystalline structure in titanium. However, in these methods, intensive plastic deformation is performed generally at a temperature above 0.3 Tm (Tm is the melting temperature of titanium), and the mean size of the elements of the grain-subgrain structure exceeds 300 nm. To reduce the size of the elements of the grain-subgrain structure after intensive plastic deformation, titanium was subjected to a special thermomechanical treatment including plastic deformation by cold rolling with annealing till recrystallization. However, the experimental data obtained are still insufficient to elucidate the mechanisms of hardening of submicrocrystalline titanium by thermomechanical treatment. Since a texture is changing during rolling, there are reasons to assume that the hardening effect of thermomechanical treatment can differ for deformation by tension, compression, bending, and torsion. In this work the effect of thermomechanical treatment of submicrocrystalline titanium on its deformation behavior and elastoplastic properties under tension at a rate of 3·10 s is investigated. The object of investigation was submicrocrystalline α-titanium VT1–0 of the following chemical composition: 0.18% Fe, 0.12% O, 0.07% C, 0.04% N, and 0.01% H (in weight %). The submicrocrystalline structure was formed by warm deep plastic deformation with a stepwise decrease of the temperature from 773 to 673 K. This submicrocrystalline structure was characterized by highand low-angle grain boundaries with relative fraction of the high-angle boundaries more than 50% and mean size of the elements of the grain-subgrain structure of 350 nm. The dislocation density inside the grains reached 2·10 cm, and the grain boundaries were imperfect [4]. Multiple rolling of titanium with submicrocrystalline structure to a total deformation degree of 40% at room temperature virtually had no effect on the size of elements of the grain-subgrain structure, but led to an increase in the dislocation density in grains and in the degree of nonequilibrity of the boundaries. At the same time, when the degree of deformation increased up to 80%, the mean size of elements of the grain-subgrain structure greatly reduced (up to 150 nm) with simultaneous increase in the fraction of high-angle boundaries (approximately up to 90%), the degree of nonequilibrity of the boundaries, the internal stresses, and the dislocation density inside the grains. The elements of the grain-subgrain structure are elongated along the rolling direction [5]. Figure 1 shows the flow curves of coarse-grained (mean grain size of 10 μm) and submicrocrystalline titanium under tension at a rate of 3·10 s at room temperature. They were calculated assuming uniform plastic deformation over the entire working length of the sample, i.e., without accounting for macrolocalization of plastic deformation before failure of the sample. It follows from this figure that in the transition from the coarse-grained structure to the submicrocrystalline structure formed during intensive plastic deformation the form of the flow curves is retained in