Sleep-disordered breathing (SDB) is not only a problem of the upper airway but is a systemic condition with endocrine and metabolic interactions. The accumulating body of evidence shows that SDB induces changes in the serum levels or secretory patterns of several hormones. Conversely, various endocrine disorders and hormone therapies may induce, exacerbate or alleviate SDB. Much of the understanding of the interactions between hormones and sleep-disordered breathing derive from intervention studies with nasal continuous positive airway pressure therapy. Better understanding of hormones and breathing may open new perspectives in developing strategies to prevent, alleviate or cure sleep-disordered breathing and its systemic consequences.