Mixtures of sunflower oil and a straight run gas oil in the diesel fuel range were hydroprocessed over sulfided NiO(3%)-MoO(3)(12%)-gamma-Al(2)O(3) incorporating 0, 15 or 30 wt.% zeolite beta (BEA). The studies were carried out at 320-350 degrees C; 30-60 bars, and weight hourly space velocities (WHSV), 1-4 h(-1). Catalyst containing 30% BEA achieved nearly 100% conversion of the vegetable oil into hydrocarbons at 330 degrees C, 60 bars and a WHSV of 2 h(-1) compared to 95.5% by the Ni-Mo-gamma-alumina catalyst without BEA. Hydroprocessing with blends containing oleic acid revealed that the catalysts were able to transform the acid into hydrocarbons. An analysis of the ratios of the n-C(18) and n-C(17) paraffins formed from the vegetable oil at different process conditions revealed that the catalyst containing 15% BEA was most active for hydro-deoxygenation. The gas oil-hydrodesulfurization activity of the Ni-Mo-Al(2)O(3) was enhanced by the addition of BEA by more than 10%. (C) 2011 Elsevier Ltd. All rights reserved.