We describe two patients with cerebral manifestations of influenza A (H1N1)v. A 13-year-old boy developed severe cerebral oedema and increased intracranial pressure despite medical treatment and external drainage of cerebrospinal fluid. He was treated with bifrontal decompressive craniectomy with good result. A 25-year-old man with a previous kidney transplant developed encephalopathy and convulsions. Magnetic resonance imaging showed encephalitis. The patient fully recovered. The cases demonstrate that influenza A (H1N1)v can cause seriously and potentially life-threatening neurological complications.