Recent advances in molecular biology and genetics have paved the way to a greater understanding of molecular mechanisms of human disease and, in particular, endocrine disorders. For example, new information concerning the structure and function of different receptors and intracellular signalling has allowed precise definition of the molecular defects involved in various disorders such as McCune-Albright syndrome, growth hormone insensitivity syndromes. Although these conditions might be rare, their susceptibility to analysis was due largely to availability and progress of the molecular biological methods. The aim of this review article is to introduce the language of molecular biology by means of a selected group of endocrine disorders.