Conjugated linoleic acid (CLA) as a derivative of linoleic acid (LA) is a generic term used to refer to a mixture of geometrical and positional isomers in which up to 16 members have been identified. CLA is unique because unlike most antioxidants which are components of plant products, is found in foods of animal origin, such as dairy products and meats. CLA concentrations in dairy foods range from 2.9 to 8.92 mg/g fat of which the 9-cis, 11-trans isomer makes up to 73% to 93% of the total CLA. Many potentially beneficial health effects have been ascribed to these fatty acids when consumed as a mixture, where generally the 9-cis, 11-trans isomer (rumenic acid) and the 10-trans, 12-cis isomer dominate. Anti-obesity, anticarcinogenic, anti-diabetic, anti-atherosclerotic, and immune modulation are among the most spectacular health benefits of CLA. The aim of this review was to show the pleiotropic biological activity of this compound (depicted in the literature recently), with particular references to its mechanisms of action.