In this study, the influence of the living conditions of red deer (Cervus elaphus) fawns (wild vs. farmed) and effect of the category of free-living animals (fawns vs. does) on the fatty acid (FA) profile of the leg bone marrow was assessed. The composition of FAs in the deer bone marrow was determined by the gas chromatography method. In all groups, oleic acid (18:1 c9) was the most abundant in deer bone marrow and comprised of approximately 37% of total FAs. The bone marrow of young wild deer was characterized by a significantly (p < 0.001) higher fat content and saturated FAs proportion, while farmed fawns contained more moisture (p < 0.005) and fat-free dry matter (p < 0.001), as well as more monounsaturated FAs cis branched-chain FAs and monounsaturated FAs trans (p < 0.001). Although no significant (p > 0.05) differences were found between fawns, in terms of partial sums of PUFA, a significantly (p < 0.001) higher level of the sum of n-3 and n-6 FAs and more favorable n-6/n-3 ratio in the bone marrow of wild fawns were determined. In general, the legs of wild fawns were better prepared for wintering than farmed ones. In turn, comparing the category-related FAs composition in the bone marrow of free-living animals, a more favorable profile was observed in the adult (does) than in the young (fawns) animals, as the bone marrow of the wild does was characterized by significantly (p < 0.001) lower percentages of saturated FAs and a higher percentage of monounsaturated FAs cis.