We have performed a urodynamic study on 3 patients with acquired immunodeficiency syndrome (AIDS), presenting with a neurogenic bladder. The first patient had an ascending myelitis of probable herpetic origin, the second patient had a cerebral abscess caused by Toxoplasma gondii, and the third patient had an AIDS dementia complex. The urodynamic study showed an areflexic detrusor in the first 2 patients, and a hyperreflexic detrusor in the third patient.