Osteogenesis imperfecta (OI) is an inherited connective tissue disorder that causes bone fragility and deformity. Neurological manifestations, including macrocephaly and hydrocephalus, have been reported. Increased vascular fragility or bleeding diathesis also predisposes OI patients to intracranial hemorrhage. The development of chronic subdural fluid collections or hydrocephalus may require CSF diversion. The authors report a previously unrecognized complication of CSF diversion in a patient with OI, that is, a delayed severe cranial deformity, presumably due to over-shunting. In addition to the cosmetic concern, the deformity caused severe headaches and tenderness. The patient underwent craniectomy and titanium mesh cranioplasty, which resulted in the complete resolution of symptoms. This report raises the possibility that over-shunting in patients with OI could predispose to the formation of cranial deformity requiring surgical intervention.