We investigate the transport properties of topological insulator (TI) nanowires. Single-crystal nanowire samples with diameters ranging from 75 nm to 1.1 m are prepared using high frequency liquid phase casting in a glass capillary; cylindrical single crystals with (101) orientation along the wire axis are produced. is a narrow-gap semiconductor with an energy gap at the L point of the Brillouin zone, meV. The resistance of the samples increases with decreasing temperature, but a decrease in resistance is observed at low temperatures. This effect is a clear manifestation of TI properties (i.e., the presence of a highly conducting zone on the TI surface). When the diameter of the nanowire decreases, the energy gap grows as 1 / d (for diameter m and nm and 45 meV, respectively), which proves the presence of the quantum size effect in these samples. We investigate the magnetoresistance of nanowires at various magnetic field orientations. Shubnikov-de Haas oscillations are observed in nanowires at K, demonstrating the existence of high mobility ( ) two-dimensional (2D) carriers in the surface areas of the nanowires, which are nearly perpendicular to the axis. From the linear dependence of the nanowire conductance on nanowire diameter at K, the square resistance of the surface states of the nanowires is obtained ( Ohm).