Compounds with dioxin-like toxicity are suspected to adversely affect human reproduction even at current background exposures. Endometriosis, a gynecological disorder often associated with infertility, has been hypothesized to be linked to dioxins and similar chemicals, a hypothesis supported by the outcome of experimental studies on animal models. Endometriosis severity and incidence in Belgium is one of the highest of the world: in this country, the general population exposure to dioxin-like compounds has been, on average, higher than in most industrialized countries. Here we show the results of a pilot case-control study carried out on 22 Italian and 18 Belgian women of reproductive age, with and without endometriosis. No significant differences were found in dioxin-like compound body burdens between cases and controls on a country basis, whereas the body burdens of the Italian women resulted to be significantly lower than that of the Belgian. In particular, total TEQs in Italian and Belgian women without endometriosis were respectively 18 and 45 pg WHO-TE/g lb. (C) 2004 Elsevier Ireland Ltd. All rights reserved.