Subdural hematoma (SDH) is a well-known sequela of ventriculoperitoneal shunt insertion for hydrocephalus, usually spreads out over the cerebral convexity, and appears as a crescent-shaped lesion on imaging. The authors report the rare case of an infant with a globular SDH, which MR imaging revealed as a round mass lesion. A 13-month-old girl with a history of severe congenital hydrocephalus associated with myeloschisis underwent ventriculoperitoneal shunt placement after repair of myeloschisis and developed convulsive seizure. Magnetic resonance imaging showed a large subdural round mass with a lesion like a pedestal in the left parietal region, suggesting a globular SDH surrounded by a thin cerebral mantle. Because of the seizures and because the hematoma did not respond to a change in valve pressure, the patient underwent a craniotomy to remove the hematoma and to resect the thick outer membranes of multiple layers. Postoperative MR imaging demonstrated the disappearance of the SDH, and no additional shunt complication was observed during a long follow-up period. To the authors' knowledge, this is the first report of a patient with globular SDH published in the literature. The authors postulate that the globular SDH was caused by the thin cerebral mantle associated with severe craniocerebral disproportion, and they discuss the possible mechanisms for this unique formation.