Neonatal Marfan syndrome is a rare condition with poor prognosis because of severe mitral and/or tricuspid valve insufficiency. Mitral valve replacement is sometimes required in early infancy, while tricuspid valve replacement is rarely done. We report the first infant neonatal Marfan syndrome case with a missense variant of c.3706T>C in the fibrillin-1 gene that was successfully managed by mitral and tricuspid valve replacement. Early multiple-valve replacement may sometimes be required during infant age in this genetic syndrome.