There is considerable concern about the increasing incidence of endocrine-related cancer and deteriorating reproductive health in humans. A large number of natural and man-made chemicals have the ability to mimic the action of the endogenous steroid hormone 17beta-estradiol by binding to and activating the estrogen receptor. Although there is no consensus regarding the role of xenoestrogens in these effects and no conclusive studies demonstrating that xenoestrogens initiate or contribute to the development of these effects. The molecular structure of exogenous natural and synthetic estrogens may be very similar to, or strikingly different from the natural hormone. Despite their structural diversity, all of the exogenous estrogens, when ingested either as natural compounds (phytoestrogens, mycoestrogens) or contaminants (xenoestrogens), have the capacitiy to bind to the ER at a given concentration in target cells of the body and can initiate (agonist) or inhibit (antagonist) estrogen-like actions. Assessment of the impact of xenoestrogenic compounds will require additional research on identification and quantitation of these compounds in serum, their interactions with plasma and cellular proteins, and their uptake in target tissues. Aim of this paper is to show the possible estrogenic effects of polcycylic aromatic hydrocarbons (PAHs), organochlorines-persistent organic pollutants (POPs) and phytoestrogens.