Since the discovery of the two cannabinoid receptors, CB(1) and CB(2), several molecules, commonly defined as endocannabinoids, able to bind to and functionally activate these receptors, have been discovered and characterized. Although the general thought was that the endocannabinoids were mainly derivatives of the n-6 fatty acid arachidonic acid, recent data have shown that also derivatives (ethanolamides) of n-3 fatty acids may be classified as endocannabinoids. Whether the n-3 endocannabinoids follow the same biosynthetic and metabolic routes of the n-6 endocannabinoids is not yet clear and so warrants further investigation. In this review, we describe the primary biosynthetic and metabolic pathways for the two well-established endocannabinoids, anandamide and 2-arachidonoylglycerol.