Propionic acidemia is an autosomal recessive inborn error of organic acid metabolism caused by deficiency of propionyl-CoA carboxylase. The main clinical features are episodic ketoacidosis, hyperammonemia, hyperglycinemia, vomiting, lethargy, and hypotonia. In this report, we describe a newborn with propionic acidemia who presented with severe persistent pulmonary hypertension (PPHN). The patient was treated with the correction of metabolic acidosis by peritoneal dialysis, and he responded well to symptomatic treatment without vasodilator therapy. It is important that determining the underlying metabolic diseases of PPHN is the most effective treatment, as seen in our patient with propionic acidemia. Anahtar Kelimeler : propiyonik asidemi, persistan pulmoner hipertansiyon, asidoz, yenidoğan.