The authors present a case of a Meckel's diverticulum identified durin
g a routine prenatal ultrasound examination as a complex mass, superio
r and posterior to the urinary bladder, that prompted meticulous postn
atal evaluation. A 4.0-cm Meckel's diverticulum containing heterotopic
gastric mucosa was excised before complications could arise. Meckel's
diverticulum should be included in the differential of a complex intr
aabdominal mass of the fetus/neonate.