As vasopressin receptors are found in many different tissues, vasopressin antagonists may benefit the treatment of numerous disorders. Effects of vasopressin via V1(a) and V2 receptors are closely implicated in a variety of water-retaining diseases and cardiovascular diseases, including heart failure, hyponatremia, hypertension, renal diseases, syndrome of inappropriate antidiuretic hormone secretion, cirrhosis, and ocular hypertension. Furthermore, V1(a) vasopressin antagonists might be useful in cerebral ischemia and stroke, Raynaud's disease, dysmenorrhoea and tocolytic treatment. V1(b) selective vasopressin antagonists are discussed in terms of their usefulness in the treatment of emotional and psychiatric disorders. The vaptans are vasopressin receptor antagonists with V1(a) (relcovaptan) or V2 (tolvaptan, lixivaptan, satavaptan) selectivity or non-selective activity (conivaptan). Conivaptan is the first vaptan which has been approved by the FDA for the treatment of euvolemic hyponatremia. For further indications such as congenital heart failure, studies are going on.