Nowadays the development and application of alternative fuels (including biofuels) are highly important for several reasons, e.g., protection of the environment and people's health and achievement of sustainable development, etc. Diesel fuels are important in road transportation in the European Union and all over the world. So, it is necessary to develop alternative (bio)fuels for diesel engines. During the development of these alternative fuels, it is necessary to take into account that it does not endanger the cultivation of food and feed crops. According to the above-mentioned reasons, we studied the catalytic hydrogenation of mixtures of the middle distillates derived from thermal cracking of waste polypropylene (WPPCF) (5-30%), waste cooking oil (WCO) (20-45%), and straight-run gas oil (GO) (50%), on a sulfided NiMo/Al2O3 catalyst to produce diesel fuel. We investigated the effects of feedstock compositions and process parameters (T = 300-360 degrees C, LHSV = 1.0-3.0 h(-1), P = 40 bar, hydrogen/feedstock = 400 N m(3)/m(3)) on the main product's quality and yield. We concluded that good quality diesel fuel blending components with high alternative component content (approximately 50%) can be produced from feedstocks having 30/20% WPPCF, 20/30% WCO, and 50% GO at advantageous process parameters (T = 340-360 degrees C, LHSV = 1.0 h(-1), P = 40 bar, hydrogen/feedstock = 400 N m(3)/m(3)).