<p>Renewable diesel is a biofuel produced via hydro-processing of glycerides and fatty acids, offering a molecular structure closely resembling that of fossil diesel. This characteristic makes it a promising alternative for partially replacing conventional fuels, as it can be blended with petroleum diesel in high concentrations or used directly in compression ignition engines without modification. In this study, the effects of blending renewable diesel derived from fatty acids obtained from waste chicken fat with petroleum diesel were evaluated by analyzing their physicochemical properties according to ASTM D975 and EN 590 standards. The renewable diesel production involved two key stages: (1) hydrolyzing chicken fat waste at 250&#xa0;°C for 120&#xa0;min, achieving a 95% conversion to fatty acids, and (2) catalytic deoxygenation of the fatty acids using a sulfurized NiMo/Al₂O₃ catalyst, yielding 92% <i>n</i>-alkanes with 99% purity. The hydrolysis step was aimed at decreasing the amount of hydrogen in the hydrotreating step. The resulting biofuel blends exhibited excellent quality, with key parameters meeting regulatory standards: kinematic viscosity of 3.18 cSt, cetane index of 79.30, flash point of 109&#xa0;°C, contamination &lt; 1&#xa0;ppm, and a filter blocking tendency of 1.03. Additionally, the cold flow properties were within acceptable ranges, demonstrating the suitability of these blends for commercial diesel applications. This study highlights the potential of utilizing waste chicken fat as a sustainable feedstock for high-quality renewable diesel production, contributing to the development of cleaner fuel alternatives.</p> Graphical Abstract <p></p>