Co-doped ZnO nanorods (Zn(1-x)Co(x)O) with x = 0.05, 0.1, and 0.2 were successfully grown on indium-doped tin oxide glass substrates via a wet chemical route at 70 degrees C for 10 h. The effect of Co-doping level on the morphology, crystalline phases, optical, and magnetic properties of the ZnO nanorods was studied. Based on scanning electron microscopy, TEM, and XRD studies, it is confirmed that Co-doped ZnO nanorods were grown along the [0001] direction. Co doping affects the d-spacing and with an increasing Co concentration, the lattice parameter c is increased slightly. The incorporation of Co in ZnO is confirmed with XPS, whereby it is shown that the excitation state of Co is (+2), which rules out the formation of a secondary phase such as Co(2)O(3) or Co(3)O(4), which is consistent with XRD phase analysis results. The near-band edge emission peak of ZnO nanorods is red shifted in response to Co doping, and the band gap energy of (Zn(1-x)Co(x)O) nanorods decreases with the increasing Co doping. Zn(0.95)Co(0.05)O and Zn(0.9)Co(0.1)O nanorods exhibit a degree of paragmagnetism, while the nanorods with higher Co concentration (Zn(0.8)Co(0.2)O) exhibit ferromagnetic behavior at room temperature.