One-dimensional (1D) platinum nanofibres (NFs) were prepared via electrospinning of Pt precursor/polymer composite fibres followed by subsequent thermal annealing. Pt-NFs several hundred micrometres long and similar to 50 nm in diameter were obtained. The internal morphology of the Pt-NFs was largely governed by thermal annealing conditions. X-ray diffraction and high-resolution transmission electron microscopy revealed a strong correlation between thermal annealing conditions and the internal grain structure of the Pt-NFs. The current-voltage (I-V) characteristics of single Pt-NF indicated that the internal grain structure of Pt-NFs plays an important role in the electrical properties of nanoscale Pt fibres.