Background <p>Microtia–atresia is a rare congenital anomaly characterized by an abnormally small external ear (microtia) with a narrow or blocked ear canal or its absence (atresia). Its incidence is between 3 and 10 cases per 10,000 live births. Microtia is bilateral in 10% of cases and in unilateral cases, the right ear is affected twice as often. Although genetic elements like chromosomal abnormalities and mutations are known to significantly contribute to the development of microtia, various environmental factors have also been linked to its occurrence.</p> Case presentation <p>This article reports a term female infant of Iranian ethnicity with microtia–atresia resulting from cesarean delivery from a 25-year-old mother. On initial examination by a pediatrician, the right external ear of the infant was underdeveloped, with an abnormal appearance and an absence of the ear canal. On closer examination, no craniofacial abnormalities or signs of possible syndromes associated with microtia were observed.</p> Conclusion <p>This report describes a rare case of isolated unilateral microtia with aural atresia in a newborn without additional congenital anomalies. Early recognition of such cases is crucial to ensure appropriate hearing evaluation, multidisciplinary management, and optimal developmental outcomes. Case reports of isolated microtia may provide valuable insights into its clinical variability and underlying etiological factors.</p>