Self-passivating tungsten-based alloys are an attractive material for application in future fusion reactors, because they combine the favourable properties of tungsten with an enhanced passive safety in the case of a loss of coolant accident. Powder metallurgical technologies have been used to prepare binary or ternary tungsten based alloys as a bulk material to improve the oxidation resistance. Silicon and chromium were chosen as the alloying elements. Elemental powder mixtures, pre-alloyed powders as well as mechanically milled powders were prepared with different alloying contents and consolidated by pressure assisted sintering technologies (hot pressing). The oxidation behaviour of tungsten alloyed with silicon and/or chromium was studied with respect to oxide growth kinetics, oxide phases and microstructure.