Undoped and Ni-doped ZnO micro-rod arrays were successfully synthesized by the spray pyrolysis method on glass substrates. Analysis of the samples with X-ray diffraction and scanning electron microscopy showed that these micro-rod arrays had a polycrystalline wurtzite structure with a highly c-axis preferred orientation. Photoluminescence studies at both 300 and 10 K show that the incorporation of nickel leads to a relative increase in the visible blue light band intensity. Magnetic measurements indicated that Ni-doped ZnO samples exhibit ferromagnetic behavior at room temperature, which is possibly related to the presence of point defects. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.