Neonatal death due to inborn error of metabolism (IEM) is rare in Malaysia. We report a sudden neonate death just a few hours after being discharged from the hospital. The deceased was a two-day-old baby boy and was asymptomatic until his demise. He was fed with expressed breast milk and formula milk. Autopsy revealed fatty changes of the liver and an enlarged heart. Laboratory investigation confirmed very long chain Acyl-CoA dehydrogenase deficiency which resulted in his death. Autopsy of sudden unexpected death in neonate should include investigation for inborn error of metabolism. Fatty liver and enlarged heart could give a clue for the diagnosis.