The term CLA (conjugated linoleic acid) corresponds to a mixture of positional and geometric isomers of linoleic acid, of which two (9/c/, 11/t/ and 10/t/, 12/c/) have biological activity. This review covers aspects related to CLA (sources, synthesis, distribution in human tissues, physiological activity), as well as its relationship with cardiovascular diseases. Most studies attribute the beneficial effects associated to the consumption of CLA to the reduction of risk factors for the development of cardiovascular diseases, such as the reduction of plasmatic triacylglycerols and cholesterol. Other research demonstrates the reduction of atherosclerotic processes. However, many studies indicate that CLA does not present beneficial effects or may even present negative effects. Thus, although there are a great number of studies related to CLA, we consider it premature to make any recommendation for the ingestion of these compounds, apart from those naturally present in a healthy diet.