A case of a 17-year-old female with a diagnosis of Prader-Willi syndrome, including mild mental retardation, compulsive eating with gross obesity and trichotillomania with trichophagia, is presented. She has a long history of multiple cognitive, behavioral, and psychopharmacological treatments, including several inpatient hospitalizations that had produced only limited success. With the introduction of a fluoxetine trial, she demonstrated a marked improvement in weight control and a moderate improvement in hair pulling over a 6-month period of observation.