Objectives: Rett syndrome (RS) is a rare disease with oral manifestations that have not been described in detail or in a standardized manner in the literature. The present study describes the oral health of the population with RS in two Spanish regions, following the protocol of the World Health Organization for conducting common oral health surveys. Study Design: A prospective, observational case-control study was carried out, involving a group of patients with RS (n1=41) and a mean age of 13.37±3.19 years, and an age- and gender-matched control group without RS (n0=82). The data referred to oral health and habits were recorded by means of a questionnaire and oral examination was used to document caries indicators (prevalence of caries, df(t), df(s), DMF(T), DMF(S) and indices referred to dental loss, morbidity, restoration), the Community Periodontal Index (CPI), and the most characteristic oral manifestations. Results: The most frequent oral habit in the patients with RS was diurnal bruxism, followed by stereotyped tongue movements and oral breathing. The caries scores were lower in the RS population than in the control group, but patients with RS showed greater periodontal alterations and a greater prevalence of drooling, dental wear, higharched palate and anterior open bite. Conclusions: The population with RS exhibits characteristic and early oral habits and alterations, and periodontal problems that are more notorious than caries disease, so that our efforts should focus on the diagnosis and early correction of the parafunctional habits, promoting restorative treatment, and providing instructions on correct oral hygiene.