Conjugated linoleic acid (CLA) has generated a great amount of interest among animal scientists worldwide because of its protective effects against cancer, atherosclerosis, and obesity and its immunomodulatory activities in animal models and humans. Therefore, it seems prudent for animal scientists to develop nutritional and management systems to increase the CLA content of animal products. Feeding CLA to beef and dairy cattle, pigs, and laying hens improves the nutritional value of meat, milk, and eggs because of their greater CLA contents. Moreover, feeding CLA to pigs improves growth efficiency, loin muscle area, and the lean to adipose tissue ratio in the carcass. Feeding CLA to beef cattle causes no change in dressing percentage, yield grades, and back fat thickness. Rounds from CLA-fed cattle are more lean. Loins of CLA-fed pigs have greater marbling and firmness. Marbling of the beef loin, however, is decreased by CLA feeding. Some measures of color (e.g., b* Hunter score) of pork loins but not all (L* and a* values) are improved by dietary CLA. The greater concentration of CLA does not influence shelf life, tenderness, juiciness, or flavor of rib steaks from cattle. A negative effect of supplemental CLA is that frequently the proportion of saturated fatty acids in the adipose tissue of pigs, milkfat, and yolks of eggs is increased. Because of the many alleged advantages of humans consuming CLA and because of the potential of CLA to improve production efficiency and quality of animal products, research on CLA will continue to be readily justifiable and necessary.