Pyroglutamic aciduria (5-oxoprolinuria) is a rare autosomal recessive disorder caused by either glutathione synthetase deficiency (GSSD) or 5-oxoprolinase deficiency. The severe form of the disease, generalized GSSD, is characterized by acute metabolic acidosis, usually present in the neonatal period with hemolytic anemia and progressive encephalopathy. We report a female infant who had a severe metabolic acidosis with high anion gap, hemolytic anemia, and hyperbilirubinemia. High level of 5-oxoproline was detected in her urine and a diagnosis of generalized GSSD was made. She died of severe metabolic acidosis and sepsis at the age of six weeks.