Noonan syndrome is a genetic disease, characterized by short stature, low posterior hairline, a webbed neck, cubitus valgus, and pectus excavatum. It may be confused with Turner's syndrome which is more frequent in the population. Pulmonary stenosis is the most frequent congenital heart disease in Noonan syndrome, though, in rare cases, atrial septal defect may also be detected. This case report illustrates the coexistence of NS and atrial septal defect in an 11-year-old girl.