Cuprous oxide (Cu2O) nanoparticles have been successfully synthesized using copper acetate as precursor via supersaturation theory as a facile rout. Synthesis parameters, such as the reducing agent concentration, reaction temperature, reaction time, type of the reducing agent and rate of adding reducing agent were investigated. The experimental results indicated that size of the Cu2O nanoparticles is dependent on the above mentioned parameters. The Cu2O samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and also by ultra violet visible spectroscopy (UV-vis). Results showed that temperature has unique influence on to the fabrication of Cu2O nanoparticles which illustrate the higher the temperature of the synthesis the smaller the particles would be. Rate of reduction was specified as an influential factor in determining the particle size distribution. Particles with crystallite size of 74.01 nm were obtained among this study.