Petroleum oil b. 160-240 degrees C (gas oil) was mixed with olive, soya, sunflower, raps and palm oils (20% by vol.) and hydrotreated with H-2 on Al2O3-supported Ni-Mo catalyst at 340 degrees C, 3 MPa and flow rate 1.5 h(-1). The lowest thermal effect was obsd. for palm oil (temp. increase 5.5 degrees C), the highest for soya oil (temp. increase 9.2 degrees C). The highest cetane no. (58) showed the sunflower oil-contg. hydroraffinate. The lowest cloud point (-8.7 degrees C) showed the palm oil-contg. hydroraffinate.