The coexistence of obstructive sleep apnea (OSA) may impose an additional risk on aortic dissection due to the possible increase in aortic transmural pressure. Thus, effective treatment for OSA, such as noninvasive positive pressure ventilation (NPPV), is thought to decrease the risk in patients with aortic dissection. We experienced one case of an OSA patient with aortic dissection who was successfully treated with continuous positive airway pressure (CPAP), resting and antihypertensive therapy. Few reports of this kind are available in the medical literature. A 55-year old Japanese man with sudden chest and back pain was admitted to this hospital. Acute aortic dissection De Bakey type 3b was observed by radiography and the patient was treated success-fully. In cases with a high likelihood of OSA with aortic dissection, application of CPAP treatment should be considered promptly along with resting and antihypertensive therapy, except if there are complications such as comorbidities or withholding of consent.