In situ formation of NbC in nanocomposite copper powders was achieved by mechanical alloying at room temperature without further heat treatment. Nominal compositions of 10 and 20 vol.% of NbC were produced from elemental powders of copper, graphite and niobium for milling times of 3.6, 7.2, 14.4, 28.8, 57.6 and 115.2 ks. As-milled Cu-NbC nanocomposites were characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD and XPS results show that NbC begins to form during the first 3.6 ks, and increases with the time of milling. The kinetics of NbC formation was studied using the results obtained from XRD and XPS experiments. A mechanism for the synthesis of NbC is proposed. (C) 2007 Elsevier B.V. All rights reserved.