Endometriosis is an estrogen-dependent disease characterized by the growth of endometrial cells in ectopic locations. Although the etiology of endometriosis is unknown, several hypotheses have been proposed to explain its origin. Retrograde menstruation of endometrial cells into the peritoneum is the most widely accepted theory, however, this phenomenon occurs in approximately 90% of women while the prevalence of endometriosis is much lower. Hence, other factors are thought to contribute to the development of this disease, including exposure to environmental toxicants. Although the epidemiological evidence is equivocal, animal and experimental investigations provide a basis for the proposed association between dioxin and dioxin-like chemical exposure and endometriosis. However, the mechanism(s) underlying this potential association are poorly understood. Development of novel animal models that more reliably recapitulate the pathogenesis and pathophysiology of this disease provide exciting opportunities to further test the link between exposure to these chemicals and endometriosis. Moreover, differential expression of several novel genes that may be important in the disease provides new targets to test the actions of environmental toxicants in the pathobiology of endometriosis.