This study details a case of Rett Syndrome where the patient's respiratory dysfunction was improved after buspirone was administered. Polygraphic studies in the waking state, before and after treatment with 5 mg of buspirone twice a day, were obtained. Breathing movements, oxygen saturation and end-tidal carbon were monitored. Average oxygen saturation increased from 86.9 to 91%, and the period of saturation below 90% was reduced by 42.2%. The oxygen saturation improvement observed in this case suggests that buspirone might be useful in treating respiratory dysfunction associated with Rett Syndrome. Controlled clinical trials are needed to provide more evidence.