Thermoelectric Bi2Te3 nanotubes were synthesized using galvanic displacement of nickel nanowires. The composition of Bi2Te3 nanotubes was precisely controlled by adjusting the [Bi3+]/[HTeO2+] ratio in the electrolyte. By combining the premagnetically assembled nickel nanowire and galvanic displacement reaction, individual Bi2Te3 nanotube-based devices were fabricated and their temperature-dependent electrical properties were measured.