A Microfactory is a set of cooperating micro-machines dedicated to the production of Microsystems in small to medium quantities. This paper describes the Microfactory concept currently developed at the Institut de Systemes Robotiques (ISR). A state of the art in this domain is presented. Several novel designs on micro-positioning systems are discussed. Emphasis is put on piezo-actuators with nanometer resolution and large workspaces (few cm3). Finally, our vision for the future trends in the field of Microfactory is briefly introduced.