The effect of the ultrafine grained silicon nitride and yttria addition to the morphological, structural, mechanical and magnetic properties of the ceramic dispersion strengthened 316 L stainless steels prepared by powder technology has been studied. Four composites have been prepared: 316 L/0.33 wt.% Si3N4, 316 L/1 wt.% Si3N4 (CDS) and 316 L/0.33 wt.% Y2O3, 316 L/1 wt.% Y2O3 (ODS). Spark plasma sintering (SPS) was used for fast compaction of milled composite powders. The hardness values have been found to be significantly higher in the cases of CDS and ODS samples in comparison to reference sample, whereas the ODS composites had lower smaller hardness than the CDS composites regardless the content of additives. The magnetic characterization of samples demonstrated that the samples exhibit ferromagnetic property already before ageing and a larger ferromagnetic component was observed as a result of thermal aging. It was proven that in the case of ODS and CDS samples with a low amount of Y2O3 or Si3N4 the saturation magnetization was slightly dependent on ageing time, however, it exhibited a noticeable change with ageing both at 600 and 800 degrees C for samples containing higher amount of additives.