According to an increasing number of applications of ceramic materials in a medical field it is a challenge to find relevant mass-production technology. Powder injection molding (PIM) is well established technique to produce small, precise, and complex-shaped metallic and ceramic parts in large volumes using injection molding. The main task in PIM is the production of the parts with a sintered density as close as possible to a theoretical of a powder used, i.e. with the lowest porosity attainable. However, ceramic items in a medical field have usually porosity requirements which are in contrast with this goal, because low content of pores inhibits cell proliferation and adhesion to substrates. This paper reports on the production of the aluminum oxide porous structures via PIM technology. Various types and concentrations of a space-holder were tested. Mixing, injection molding, debinding and finally sintering steps of the PIM process have been optimized and related to the final porous structures obtained.