Rett syndrome is a progressive neurological disorder that occurs exclusively in females. The syndrome is characterized by regression of language, motor development, and stereotypic hand movement. Autistic behavior, breathing irregularities, gait dyspraxia, scoliosis, and seizure are also accompanied. The cause of Rett syndrome is unknown, however, it is believed that the X-chromosome might playa significant role in the development of the syndrome. Patients with this syndrome have unusual oral and/or digital habits such as abnormal chewing pattern, bruxism, hypersalivation, micrognathia, high vaulted palate, tongue protrusion with lower posture of tongue, hand biting, digit-hand sucking. Dentists who are aware of distinct manifestations of Rett syndrome will be able to aid in early diagnosis and treatment of the syndrome. Prior to dental treatment for a patient with the Rett syndrome under sedation or general anesthesia, one should assess the degree of hypersalivation, apnea, severity of autism, expected life span. Early recognition of the syndrome and also dental treatment with established strict preventive guidelines for patients with the Rett syndrome may obviate the necessity of sedation or general anesthesia. Two cases with the Rett syndome were reported. Both patients had most of the above mentioned typical manifestations of the syndrome. Dental treatment for the case 1(8-year-old) including caries control, stainless steel crown, sealant application was performed under general anesthesia. The case 2 could not be undergone the dental treatment due to poor general conditions.