Duplex stainless steels are characterized by a microstructure that combines equal amounts of austenite and ferrite and that pursues a good combination of strength and corrosion resistance. Duplex stainless steels obtained by powder metallurgy (PM) can be produced by different routes and could be used in many industrial branches. Here the use of prealloyed austenitic and ferritic powders was investigated and the production of a porous product (sintered filters) was considered. Water atomized commercial AISI 304 and 410 stainless steel powders, classified between 100 and 325 mesh, were used as raw material. Cylindrical samples having an external diameter of 15mm, an internal diameter of 10mm and 28mm high were pressed and vacuum sintered. Some aspects of sintering were evaluated by calorimetric measurements. Microstructural features were investigated by X-ray diffraction and microscopy. The air permeability of samples were determined.