Neonatal Marfan syndrome is a severe form of the syndrome mostly caused by de-novo mutations in the fibrillin-1 gene. We report a newborn with neonatal Marfan syndrome and functional pulmonary atresia who died from congestive heart failure on postnatal day 22 despite treatment. He had a mutation in exon 29 of the fibrillin-1 gene at position c.3602G>A. Functional pulmonary atresia may be a life-threatening cardiovascular manifestation of neonatal Marfan syndrome.