Objective : Rett syndrome is a neurological disorder occurring primarily in girls. By process of treatment for a case which was diagnosed as Rett syndrome and out patient department treatment from the 12th, April, 1999 to November, 2001, the results are as follows. Method & Results : This patient was diagnosed as five-development disorders categories(五遲, 五軟), medicated with Yukmijihwang-tang(Liuweidihwang-tang, 六味地黃湯) and Kyejigayonggolmoryu-tang(Guizhijialonggu-tang, 柱枝加龍骨牡蠣湯). And acupunture therapy was taken on Shinjyungkyuk(shenchongge, 腎正格) and Paekoe(百會 GV 20), Taechu(大椎 GV 14), Renzhong(人中 GV 26). As a result, the patient's hypotonia and intermittent seizures were improved. Conclusion: Rett syndrome is most often misdiagnosed as autism, cerebral palsy or non-specific developmental delay. In oriental medicine, RS can be diagnosed as five development disorders categories (五遲, 五軟) and oriental medication with acupuncture treatment can improve RS patient's conditions.