<h2>Abstract</h2> Hormone replacement therapy is available for patients suffering diabetes insipidus and all the anterior pituitary hormone deficiencies, with the exception of prolactin. In patients with adrenocorticotrophic hormone and thyroid-stimulating hormone deficiencies, replacement is with the target-gland hormone products cortisol (hydrocortisone) and thyroxine, respectively. Sex steroid replacement therapy is offered to patients with gonadotrophin deficiency to deal with the sex steroid deficiency, but if fertility is desired gonadotrophin therapy is required. Growth hormone (GH) deficiency requires GH replacement, but only adult patients with severe GH deficiency are considered for replacement and, in the UK, such patients are chosen by virtue of severe impairment of quality of life; strict criteria must be satisfied before the 9-month trial of therapy can be extended to lifelong GH replacement. Desmopressin, a synthetic analogue of arginine vasopressin, is the drug of choice for the treatment of antidiuretic hormone deficiency; it is available in several different preparations.