We describe mitochondrial trifunctional protein deficiency (MTPD) in two male siblings who presented with severe cardiomyopathy in infancy. The first sibling presented in severe cardiac failure at 6 months of age and succumbed soon after. The second sibling came to attention after newborn screening identified a possible fatty acid oxidation defect. Dietary therapy and carnitine supplementation commenced in the neonatal period. Despite this the second child required cardiac transplantation at 3 years of age after a sudden and rapid decline in cardiac function. The outcome has been excellent, with no apparent extra-cardiac manifestations of a fatty acid oxidation disorder at the age of 7. Pathogenic HADHA mutations were subsequently identified via genome wide exome sequencing. This is the first reported case of MTPD to undergo cardiac transplantation. We suggest that cardiac transplantation could be considered in the treatment of cardiomyopathy in MTPD.