A unique syndrome consisting of episodic hyperpnea, abnormal eye movements, ataxia and mental retardation, associated with agenesis of the cerebellar vermis, has been delineated in four siblings by Joubert et al. (1969). We describe three other children with this clinically recognizable condition which we suggest to call Joubert syndrome. There is good evidence that it is inherited as autosomal recessive. Two of out patients were brothers, the third child's parents were related. Recognition of this syndrome is important in view of prognosis and for genetic counseling.