Cardiac function depends on provision of blood-borne substrates to maintain adequate myocardial metabolism. Metabolic substrates vary in efficiency and energy yield, and the ability to flexibly switch between substrates according to varying pathophysiological states is key to maintaining adequate cardiac function. Cardiac utilisation of carbohydrate in the form of glucose, and lipid in the form of non-essential fatty acids, is well defined, but cardiac utilisation of triacylglycerols (triglycerides; TAG), a potentially large source of exogenous energy, has been harder to examine. Studies defining cardiac TAG utilisation in a variety of pathophysiological states, their selection preference and their contribution to cardiac function, will be discussed. Novel issues of routes of cardiac TAG uptake, and the potential role of TAG-rich lipoproteins as metabolic signals, will also be discussed. DPAG