An experiment was conducted with Holstein-Jersey steers (n=60, 996±4 lb initial body weight) to examine live performance, carcass characteristics, and fatty acid profiles of loin tissue from feedlot steers fed diets supplemented with flax oil and flax oil derivatives (flax = flaxseed throughout paper). Cattle were fed corn-based diets with no supplemental fat (CON), flax oil (OIL), lipase treated flax oil (L-OIL), or linseed soapstock (SOAP). Steers were blocked by weight and randomly assigned to concrete-surfaced pens (5 animals/pen, 3 pens/treatment). At the end of the 90-day finishing period, cattle were shipped to a commercial abattoir and carcass data were obtained. Rib sections were removed from one side of each animal for determination of fatty acid profiles. Daily dry matter intakes were highest for the CON, lowest for L-OIL, and intermediate for steers fed OIL and SOAP. There were no differences among treatments with respect to average daily gain, gain efficiency, or final body weight. Also, carcass characteristics were similar for all treatments. Steers fed diets supplemented with different sources of flax lipids produced loin steaks with higher concentrations of alpha-linolenic acid and total omega-3 fatty acids compared to steers fed the CON diet. Overall, hydrolyzing flax oil with lipase decreased dry matter intake compared to other treatments, perhaps indicating a negative effect of feeding high levels of free fatty acids. Supplementing flax oil and flax oil derivatives increased concentrations of omega-3 fatty acids in loin tissues of feedlot steers, but linseed soapstock and lipase-treated oil were inferior to flax oil as a strategy to increase omega-3 fatty acid concentrations in beef tissue.