Tin oxide (SnO2) nanoparticles have been successfully prepared by using co-precipitation route using tin chloride and sodium hydroxide as tin source and precipitating agent, respectively. Fourier transform infrared spectrum, x-ray powder diffraction, scanning electron microscope, energy dispersive x-ray spectroscopy and transmission electron microscope were used to characterize as-prepared and heated samples. The broad XRD peaks were corresponding to small crystallite nanoparticles. Grain size of particles has been obtained around 6 nanometers using XRD patterns and Scherer’s formula. SEM images were shown rod morphology of nanoparticles and also one can see a good monodispirsity of rods. The particle size was obtained less than 20 nm using TEM images. Nice superparamagnetic property was obtained when the samples calcinated at 200 °C. The particle size decreased as doping amount increasing.