We examined the clinical characteristics of six right-handed patients who developed speech motor control disorders after human immunodeficiency virus (HIV) infection. They exhibited an ataxic dysarthria, characterized by irregular articulatory breakdowns in consonant and vowel timing; were slow in timed decision-making tasks; and had impaired procedural learning. Other aspects of the neurologic examination revealed signs of diffuse CNS involvement including action-intention tremors, ataxic gait, and release signs. None developed HIV-associated dementia during 1 year of follow-up. Motor speech control disorder appears to be related to a cerebellar dysfunction.