The effect of elemental silicon addition to austenitic stainless steel powder on the mechanical properties of sintered specimens has been investigated. It has been recognized that addition of silicon powder to sintered stainless steel affects the pore morphology, microstructure, mechanical properties and corrosion behaviour. Second phase, ferrite, formation within the austenite matrix was not observed up to a silicon content of 4 wt% when sintering in Dissociated Ammonia at 1120°C. At a higher sintering temperature of 1280°C, ferrite started to form at a content of 2.5 wt% silicon. The ferrite fraction rises sharply at a silicon content of 4 wt% increasing the hardness of the specimens while a decrease in the elongation values has been observed. The pore morphology improved due to the formation of a transient liquid phase, yet the residual porosity exhibited large rounded pores. The established Ultimate Tensile Strength (U.T.S) and Yield Point (Y.P) values are lower than in austenitic stainless steel sintered without any additive, due to the basic mechanical properties of the ferritic (B.C.C) phase. Although the specimens exhibited a transient liquid phase mechanism, an overall detrimental effect has been observed on the mechanical properties. Coarse particle size silicon powder addition lowers the mechanical properties and the corrosion resistance of the specimens but in increases the hardness of the individual grains. Fine particles silicon powder addition render better properties, mainly the corrosion resistance.