The use of renewable energy sources is continuously growing worldwide. The demand for alternative fuel components from renewable sources in Europe is also increasing. To ensure economically sustainable transport and shipping, it is inevitable that the production of alternative fuels from waste sources will be increased. The aim of this research work was to produce high quality, alternative components containing diesel fuel and to study the hydrogenation and the interaction among the different compounds of the waste polyolefin cracking fraction (10 %), waste fatty acid fraction (10, 20 and 30 %) and the high sulphur gas oil. The catalytic conversion of the mixtures was carried out on a commercial, sulphided NiMo/Al2O3P catalyst. High-quality diesel fuel component with high hydrogen content (13.65 %), high cetane number (57.0) and reduced expected emissions was produced under the favourable process parameters (temperature: 360 °C, hydrogen/hydrocarbon volume ratio: 600 Nm3/m3, pressure: 50 bar, and liquid hourly space velocity: 1.0 h-1). The obtained product is more environmentally friendly than conventional diesel fuels and can contribute to reduce the amount of landfilled wastes.