AbstractTrace amounts of the following saturated normal (both odd‐ and even‐numbered) and branched‐chain fatty acids have been isolated and identified in hydrogenated ox perinephric fat: n‐decanoic, n, dodecanoic, n‐pentadecanoic, 13‐methyltetradecanoic (+)−12‐methyl‐tetradecanoic, n‐nonadecanoic, n‐eicosanoic, n‐heneicosanoic, n‐docosanoic, n‐tricosanoic, n‐tetracosanoic, and n‐hexacosanoic acids. In addition, n‐undecanoic and n‐tridecanoic acids were identified. Myristic, palmitic and stearic acids present in more than trace amounts were also conclusively identified.