The hallmarks of sleep apnea syndrome include daytime hypersomnolence, snoring, obesity, disturbed nocturnal sleep, and apneic episodes. Thyroid deficiency states are now a well recognized cause of sleep apnea. Central, obstructive, and mixed patterns of sleep apnea may be observed in hypothyroidism. A 33-yr-old man was admitted complaining of daytime hypersomnolence, snoring, sleep apnea and obesity. A polysomnogram showed obstructive pattern of sleep apnea syndrome. Physical examination and hormonal study revealed a narrowing of the upper airway and primary hypothyroidism. Dilated cardiomyopathy was diagnosed by echocardiogram. The poctients was treated for obstructive sleep apnea syndrome with nasal continuous positive airway pressure(CPAP) for 2 months and the underlying hypothyroidism with thyroid hormone therapy. This successfully controlled the snoring, sleep apnea, and other apnea-related symptoms. Here, we describe our experience of nasal CPAP and thyroid hormone therapy in a patient with primary hypothyroidism associated with obstructive sleep apnea syndrome and dilated cardimyopathy with review of the relevant literature.