Copper oxide (CuO) nanoparticles have been prepared by solution combustion method using citric acid as fuel. The structure and morphology of the CuO nanoparticles were investigated by means of X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersion spectra (EDS) techniques. The rod like nature and monoclinic crystalline structure of the prepared CuO nanoparticles were revealed from FESEM, HRTEM and XRD. The CuO NPs showed very good antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Photocatalytic activities of CuO nanorods were also investigated. (C) 2012 Elsevier B.V. All rights reserved.