Life organization requires a sophisticated communication system between and inside cells; it has been well preserved throughout evolution. The hormones are the main leaders of this messenger system, which becomes more and more complex in multi-cellular beings. They act in the nervous and reproductive systems, and are sensitive to environmental interactions. For one half of acentury of intensification of the industrial era, more than 5 million man-made chemicals have been released in the environment without recycling, as if the ecosystems were infinite. These products were often designed either to be stable, as being rather insoluble (plasticizers – phthalates, PCB -, diverse oil residues, inks, insulating or other industrial residues like heavy metals...), and/or to be penetrating and active on the physiology of organisms (drugs, pesticides such as herbicides, insecticides, fungicides, raticides, etc.). These xenobiotics become excellent candidates for the disruption of the hormonal messenger system - known as endocrine - in the organisms, as well as the nervous system. They also disturb steroid metabolism, i.e. they are often oxidized through the cytochrome P450 family, making them close to estrogenic structures when they come from polycyclic hydrocarbons. There are also natural families of compounds with estrogenic effects, such as phytoestrogens, in soy and other vegetables, and mycoestrogens. This review will focus on the recent knowledge about these endocrine disruptors (EDs) that are present in all organisms, with recently discovered and unexpected modes of action. They act noticeably on the synthesis, storage, production, and transport of hormones themselves (steroidogenesis in particular), but also on metabolism, fixation, action or elimination of hormones, and not only on the direct modification of their effects. EDs also interact on epigenetics, which may influence gene expression over several generations. Moreover, EDs are likely to cause mutations contributing to genetic diseases.