Animal fats are valuable food ingredients owing to their technological, sensory, and functional properties. This study evaluated the influence of animal species and adipose tissue origin on physicochemical characteristics, fatty acid composition, oxidative stability, volatile compound profile, colour, and thermal behaviour of beef tallow and pork lard obtained by low-temperature vacuum rendering (90 ± 2 °C, 200 mbar). Beef visceral, subcutaneous, and groin fat, as well as pork leaf, back, jowl, and groin fat, were rendered under identical processing conditions. Significant differences in fatty acid composition were observed between the analysed fats (P < 0.05). Compared to beef fats, pork fats contained higher proportion of polyunsaturated, omega-3, and omega-6 fatty acids, whereas beef fats had more trans and selected saturated fatty acids. Beef fats were characterised by higher oxidation onset temperatures, indicating greater thermo-oxidative stability. Significant differences were also found in peroxide value, malondialdehyde (MDA) content, colour parameters, and volatile compound profiles. Principal component analysis differentiated the rendered fats according to their volatile fingerprints, reflecting the effects of both animal species and adipose tissue origin on aroma characteristics. Despite compositional differences, all rendered fats showed low acid values, peroxide values, and MDA contents, indicating limited hydrolytic and oxidative deterioration under the applied rendering conditions. These findings indicate that the quality characteristics of rendered fats varied between samples from different species and anatomical fat depots, while low-temperature vacuum rendering was associated with generally favourable lipid composition and limited oxidative changes.