The metal-organic chemical vapour deposition (MOCVD) method has been used to grow Cu nanorods without metal catalysts. Pentagonal bat-shaped Cu nanorods (Cu nanobats) with five-fold symmetry were successfully synthesized by MOCVD without capping reagents. The average diameters of the head and tail of the Cu nanobats are 100 and 50 nm, respectively. The Cu nanobats are evolved from multiply twinned particles with a decahedral shape. Both elongation along the five-fold symmetry axis and lateral growth of exterior twins were found to be important in the growth of pentagonal Cu nanobats. The Cu nanobats possess strong field emission characteristics.