Neurologic signs and symptoms may represent the initial presentation of AIDS in 10-30% of patients. Movement disorders may be the result of direct central nervous system infection by human immunodeficiency virus (HIV) or the result of opportunistic infections. We report the case of a 59 years old woman who had hemichorea-hemiballismus subsequently found to be secondary to a cerebral toxoplasmosis infection revealing HIV infection. Movement disorders, headache and nausea were resolved after two weeks of antitoxoplasmic treatment. Brain MRI control showed a marked resolution of cerebral lesion. Occurrence of hemichorea-ballismus in patient without familial history of movement disorders suggests a diagnosis of AIDS and in particular the diagnosis of secondary cerebral toxoplasmosis. Early recognition is important since it is a treatable entity.