BackgroundPenile duplication or diphallia is a rare congenital anomaly with unclear pathophysiological cause. Most cases of diphallia are reported postnatally; however, today with the use of a high-resolution ultrasound device, in-uterine diagnosis of many congenital anomalies is possible.Case presentationHerein we report a multiparous mother at 25 weeks of gestation who referred due to an abnormal cystic structure protruding from a large abdominal wall defect located below the umbilicus that was noted during a routine exam. Target scan revealed two penile-like protrusions with an empty scrotal sac and double bladder in an otherwise normal fetus, which was confirmed postnatally. Neonatal microarray study and karyotype were normal.ConclusionDiphallia could be detected prenatally as an isolated anomaly, associated with caudal duplication syndrome, or as an exstrophy-epispadias complex. As this is a rare congenital anomaly, all sonographers should be familiar with prenatal ultrasound features and associated anomalies, an important issue in prenatal counseling with parents, delivery planning, psychological support of the family, and postnatal management.