Stainless steel matrix composites were manufactured using powder metallurgy techniques. Matrixes of AISI 316L stainless steel were reinforced with yttria or alumina particles. Chromium diboride was added in some cases and boron nitride in others to obtain steels with densities close to theoretical, using reactive (liquid phase) sintering techniques. The composites showed very good densification and better hardness than the 316L stainless steel without additions. The 316L steel reinforced with 4 wt-% yttria chromium diboride showed the highest density and strength, with an acceptable corrosion resistance.