Ring 18 syndrome or ring chromosome 18 is an extremely rare genetic disorder involving the fusion of the 18th chromosomal ends to form a ring, often with genetic material loss of varying degrees. Although clinical presentation can be extremely variable, characteristic features usually include craniofacial malformations, delayed development, hypotonia, and other skeletal and congenital heart defects. We report the management of a 20-year-old male with ring chromosome 18 who underwent general anesthesia for dental treatment. Clinical manifestations for this patient included intellectual disability, short stature, hypertelorism, flat nasal bridge, micrognathia, a "carp-shaped" mouth, and aortic and pulmonary valve regurgitation. Although mask ventilation and oral intubation were easily performed, nasal intubation was difficult because of rhinostenosis. When providing general anesthesia for a patient with ring chromosome 18, anesthesiologists should evaluate the patient preoperatively for congenital heart defects and prepare for a potential difficult airway. © 2021 by the American Dental Society of Anesthesiology.