Catalytic hydrodeoxygenation (HDO) of fatty acids has been investigated using different feedstocks for renewable diesel production. Two types of catalysts were studied: sulfur-free nickel supported on H-Y zeolites, γ-Al2O3 and SiO2, and palladium supported on active carbon as a noble metal catalyst. Preliminary HDO experiments were carried out on these catalysts in a semi-batch reactor at 300 °C in H2 under a total pressure of 30 bar for 6 h with stearic acid as a model for fatty acids. An in-depth comparative study of Ni/H-Y and Pd/C was performed in HDO of fatty acid methyl ester (FAME) obtained from the Chlorella microalga, tall oil fatty acids (TOFA) and animal fat. HDO experiments revealed that Ni/H-Y was a better catalyst for this process providing higher activity for different fatty acids. Ni supported on γ-Al2O3 and SiO2 provided complete conversion upon testing in HDO of stearic acid while total HDO over Pd/C was not reached.