Loeys–Dietz syndrome is a recently recognized connective tissue disorder characterized by severe craniofacial and skeletal abnormalities as well as arterial tortuosity with aggressive aneurysm formation. Marfan syndrome, a classic connective tissue disorder, is known to be associated with a risk of obstructive sleep apnea, but sleep-related breathing disorders have not been previously documented in Loeys–Dietz syndrome. The propositus had the prototypic features of Loeys–Dietz syndrome with a de novo mutation in TGFBR2. He developed severe obstructive sleep apnea during his infancy. Continuous positive airway pressure was introduced at age 7 years and provided significant improvement in his nocturnal apnea and sleep apnea-related symptoms, such as enuresis. Marfan syndrome is known to be associated with a high risk of sleep apnea because of its characteristic craniofacial and connective tissue abnormalities. Similarly, the severe craniofacial abnormalities in Loeys–Dietz syndrome may predispose patients to severe obstructive sleep apnea, even at a very young age. Despite the severity of obstructive sleep apnea in the propositus, the administration of continuous positive airway pressure was highly effective in alleviating his symptoms. In summary, severe obstructive sleep apnea was successfully treated using continuous positive airway pressure in a patient with Loeys–Dietz syndrome. Careful evaluation and aggressive intervention for the alleviation of obstructive sleep apnea is warranted in Loeys–Dietz syndrome. © 2013 Wiley Periodicals, Inc.