Medium-chain acyl CoA dehydrogenase deficiency (MCADD) and other inborn errors of metabolism are common causes of Sudden Unexpected Deaths in Infancy (SUDI). If identified early or before metabolic decompensation, MCADD is manageable. In the US and other countries, identification of MCADD has improved through the routine use of newborn screening (NBS), which is able to identify most cases. This case study presented here occurred before NBS was implemented in Ohio for MCADD and outlines the typical clinical presentation, pathological features, and relevant biochemical and molecular markers for identifying MCADD. Genetic counselling should be sought for the family if MCADD is identified.