A 45-month-old child who had bitemporal arachnoid cysts and macrocephaly unrelated to glutaric aciduria type 1 (GA 1) was reported. The patient was admitted to the emergency unit after head trauma at 11 months of age. CT and MRI showed bitemporal arachnoid cysts (BACs). Acylcarnitine profile was normal in serum using tandem mass spectrometry. Urine and blood screening tests were within normal range for metabolic disorders. There were no unusual organic acids in urine and blood samples. No additional clinical findings of metabolic disorders such as GA 1 developed during follow-up. The majority of children affected with GA 1 have macrocephaly and BACs on CT or MRI. These signs should alert neurosurgeons to the possibility of GA 1. Neurosurgeons evaluating patients with head trauma or suspected non-accidental head injury should include GA 1 in the differential diagnosis of BACs associated with macrocephaly, and an evaluation should be performed.