Prader-Willi syndrome (PWS) is a rare genetic disorder reported rarely in dentistry. Dental practitioners should know the features of PWS because affected patients have a variety of dental symptoms. The current report describes a case of PWS. An 18-year-old male patient presented with traumatic injuries. Initial emergency treatments were performed under sedation, and further treatments were conducted under general anesthesia. After adequate healing, periodic follow-up and dietary management according to the patient's age and nutritional phase were recommended. Dental management of PWS patients consists of active preventive measures in addition to dietary consultation according to age and nutritional phase.