Isovaleric acidemia (IVA) is an autosomal recessive disorder of leucine metabolism caused by isovaleryl-CoA dehydrogenase (IVD) deficiency. IVA can appear from the neonatal period to adulthood. In infancy and childhood, clinical findings include recurrent vomiting, lethargy, convulsions, swe-atyfoot-like body odor, and laboratory findings include metabolic acidosis, cytopenias and hyperammonemia. Blood amino acids, urine organic acid analysis and genetic tests are performed for differential diagnosis. In this article, we present a case of isovaleric acidemia in an 8-day-old infant who presented to our neonatal outpatient clinic with jaundice, deterioration in feeding and decreased movements.