Rett syndrome is a common developmental-neurologic disorder that has been reported almost exclusively in females. Recent work has improved recognition of this condition and helped to clarify the management of this disorder for affected individuals. The primary-care physician can become a major source of support and advocacy for the family of a girl with Rett syndrome. Many other resources are available to the primary care giver and the families of children with Rett syndrome; these may help to provide early diagnosis, psychological support, and preventive medical care for these individuals. The current state of knowledge regarding Rett syndrome is reviewed and a framework is provided for medical and developmental interventions.