This study is devoted to a thorough crystallographic and microstructural characterisation of gold nanowire arrays. The nanostructures were produced by directional solid-state decomposition of the Fe-Au eutectoid. The system structure and microstructure were investigated using differential thermal analysis (DTA), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM) and scanning Auger electron microscopy (SAEM). The most relevant sample features, with particular attention to the microstructure evolution, morphology and crystal-lography of the gold nanoarrays, are critically discussed. Gold nanofibres exhibit a faceted morphology with an average width of 20 rim, length of 100 nm and inter-wire distance of 250 nm. HRTEM analysis revealed that the obtained nanostructures are single crystalline and that the fibre-matrix crystallographic orientation relationship is of the Nishiyama-Wassermann type. (C) 2008 Elsevier Ltd All rights reserved.