A 12-year-old female diagnosed with human immunodeficiency virus infection at age 1 was admitted to our hospital with complaints of headache, left hemiparesis, and blurry vision. On admission, her CD4+ count was 97 cells/mm(3) (13%) and her viral load 44,783 ribonucleic acid copies/mL. Treatment had been initiated 3 months before admission with lopinavir/ritonavir, lamivudine, and stavudine. A computed tomographic scan and magnetic resonance imaging of the head revealed an aneurysm of the right middle cerebral artery. A head angiographic scan was consistent with intracranial arteritis. Six months after the initiation of antiretroviral therapy, her CD4+ cell count was 226 cells/mm(3) (16%) and her viral load was undetectable (less than 50 copies ribonucleic acid/mL). Magnetic resonance angiography of the head performed 15 months after the diagnosis demonstrated resolution of the aneurysm and the intracranial arteritis. This case highlights the association of human immunodeficiency virus infection with the occurrence of intracerebral aneurysms in the context of human immunodeficiency virus-vasculopathy, as well as its improvement with highly active antiretroviral therapy.