Estrogens are known to influence genetic expression by interfering in cell growth and differentiation through different mechanisms, both in organs associated with reproduction and in other areas. Recently, the number of studies investigating these receptors in different tissues by means of the immunohistochemical method has been increasing. Another method that has also been used recently is investigation of the expression of RNA-m at the specific receptors by means of PCR. The effects of estrogen have been analyzed in relation to a significant number of tissue types that are not associated with reproduction, for example bones and the cardiovascular, gastrointestinal, immunological and central nervous systems. Hence, the aim of the present study was to review the literature on estrogen receptors in non-target organs for the action of this hormone, ie in organs that are not associated with reproduction.