A study was made to determine the effects of diet upon the fatty acid composition from several sites of hog depot fat. The leaf fat and backfat from hogs fed safflower oil was less saturated than that from controls. This difference was mainly due to palmitic acid. Fat from hogs fed safflower oil contained significantly more linoleic acid and significantly less oleic acid than the fat from control hogs. Feeding tallow tended to restore the fatty acid pattern of safflower oil-fed hogs to that of control animals. It was found that the major fatty acid changes due to diet occurred within 4–5 weeks. Diet can alter the fatty acid composition of pork fat to an extent where lard may have a favorable effect upon maintaining low serum cholesterol levels in humans. However, the adverse effects of the triglyceride structure of lard upon this phenomena must be further investigated. The fatty acid composition of the intramuscular fat from the l. dorsimuscle was affected much less by diet than was that of the leaf fat or backfat. Data suggest that the inner layer of backfat exhibited a more extensive turnover of fatty acids than the outer layer. The leaf fat and backfat from barrows contained more palmitic and stearic acids and less linoleic acid than did similar fat samples from gilts. There was no difference in the fatty acid composition of the intramuscular fat between barrows and gilts. It was found that there was no significant difference for tenderness, juiciness, flavor, over-all acceptability and Warner-Bratzler shear values for loin samples due to treatment.