Conjugated linoleic acid (CLA) consists of a group of geometric and positional isomers of linoleic acid. CLA has been shown to improve animal performance, and composition, be anticarcinogenic, antiatherogenic, and improve immune function. To test the hypothesis that dietary CLA would improve performance and quality characteristics of pork, forty crossbred pigs (8 replications) were fed diets containing 0, .12, .25, .50 or 1.0% CLA by weight of the diet from 26.3 to 114 kg. Average daily gain (P < .05) and gain/feed (P < .05) were improved. Fat depth at the 10th rib decreased as the amount of CLA in the diet increased (P < .05). Ultrasound showed an increase in muscling, but no differences in loin eye area were observed on carcasses. Belly hardness (firmness) increased linearly with an increase of dietary CLA supplementation both lean side up (P < .01) and lean side down (P < .05). CLA as a percentage of total lipids increased (P < .01) in both subcutaneous fat and lean tissue. Day one postmortem loin chops exhibited no differences between controls and CLA supplemented chops for pH, water holding capacity and Warner-Bratzler shear force, and a significant linear increase (P < .05) occurred in Hunter a* (redness) as the amount of CLA in the diet increased. A trained sensory panel found that day one controls exhibited more initial juiciness (P < .05) than did the. 12% dietary CLA supplemented loin chops. No other sensory panel differences were detected. No differences were determined between 1.0% CLA treatments and controls for Hunter color, sensory panel scores, and cook loss or drip loss of loin chops held for 7, 14, 28 or 56 days of fresh storage. A preliminary study of 70/30 fresh pork patties held for 1, 3, 7, or 14 days of fresh storage as measured by Hunter L*, a*, and b* values suggested that CLA supplementation up to .50% enhanced/maintained patty color. Immune response and blood chemistry parameters were measured at 52, 68, 91, and 114 kg live weight. Immune response was not compromised and blood chemistry parameters indicated no pathological conditions as a result of dietary CLA supplementation.