Silver promoted nickel catalysts supported on diatomite were prepared by precipitation method. Characterization of the catalysts prepared with different silver contents (0.1-4.0 wt%) included AAS, XRD, Hg porosimetry, BET and H-2 chemisorption measurements. The catalytic activity and selectivity were tested by soybean oil (SBO) hydrogenation under pressure of hydrogen of 0.16 MPa at 160 degrees C. Fatty acids (FA) contained in hydrogenated SBO were analysed by gas chromatography. Trans fatty acid (TFA) content in hydrogenated SBO varied considerably depending of the silver content in prepared catalysts.