In this study, the injection speed control of computer controlled powder injection molding machines, driven by electro-hydraulic servovalves, was investigated both theoretically and experimentally. It is known that controlling the injection speed affects highly the quality of powder metal or ceramic parts produced by powder injection molding technique. For this purpose, first, the advantages and disadvantages of the studies carried out in this field were investigated. Then, a detailed system model of a powder injection molding machine was developed and the parameters affecting mostly the system behaviour was determined by carrying out theoretical simulation studies. In the light of obtained data, a closed loop control system was designed and manufactured, an accurate control of the machine were realized. Comparisons were made between theoretical and experimental results, and the findings are discussed.