This paper presents the procedures required to determine the locations and sizes of multiple-Active Power Filters (APFs) to reduce harmonic distortion in a power system with harmonic sources. The objective function is to minimize the APFs injection currents while satisfying harmonic voltages, total harmonic voltage distortions within IEEE-519 recommended limits and the maximum rating current limit of each installed APF. The APFs are located at the points having harmonic sources or higher harmonic distortions, while minimizing injection currents. The ANN Model is developed to determine size and location of APF. A typical 28-bus distribution system is selected to verify the validity of the proposed procedures.