Objectives. The goal of this work is to study and develop an electrical integrated system that allows the control of the basic functions (such as micturition, defecation, and erection) by sacral root stimulation in paraplegic patients. Materials and Methods. The system has been implemented using a commercially available Mietec CMOS technology. It is based on an external transceiver unit, which provides data and energy to the implant device through a bi-directional inductive link, and an implantable batteryless module that generates the needed current pulses, according to the orders received from the external unit. To test the electrode-tissue interface and system performance, an impedance measurement circuit has been included. Results. The three independent channel stimulators allow an exhaustive control of the waveform parameters (amplitude, pulse width, frequency) independent of the placement of the external coil respect to the internal device. Conclusion. The architecture of the new stimulator, applied over the sacral roots, can be used to control the voiding of the bladder. The system allows an independent distance programmable stimulation. The impedance measurement circuit implemented allows an easy and systematic performance test.