Pneumocephalus, intracranial air or gas collection, associated with neonatal meningitis is extremely rare. We report the first case in the United States and the second case in the world of intracranial gas accumulation in a neonate with Citrobacter koseri meningitis. The clinical presentation was acute with pneumocephalus demonstrated by cranial sonography and computed tomography. The clinical course was fatal despite the prompt administration of antibiotics.