In order to produce monodispersed particles, two requirements are considered; they are a complete separation of nucleation and growth steps for the formation of particles and an avoidance of their aggregation during the nucleation and growth. In this study, a new method was presented for preparing narrowly size distributed copper powders from CuO slurry by wet chemical reduction with hydrazine used as a reductant. The rapid nucleation was first induced by a very fast reduction of Pd2+ resulted from batch process. Subsequently copper species which contribute to the growth on the formed Pdo nuclei was slowly generated by semibatch process. A complete separation between nucleation and growth therefore was obtained, resulting in a narrow size distribution of final Cu powder product. The effect parameters on the growth such as Pd2+ concentration and temperature were also investigated.