Endometriosis is usually described as a complex multifactorial disease involving dysregulation of estrogen metabolism, inflammatory and immunological mechanisms. Recently, many authors have questioned the environmental pollution and toxins in the formation and development of endometriotic lesions. Therefore, while dioxins and PCBs have been implicated, insufficient data are available until now to confirm this theory. Endometriosis has also been considered as a genetic disease. Indeed, early familial aggregation and twin studies noted a higher risk of endometriosis among relatives. However, demonstration of a genetic component in the pathogenesis of such a multifactorial disease is quite difficult due to many limitations such as ethnic differences, involvement of environmental factors and size of needed patients cohorts. Over the last decade, the epigenetic approach (DNA methylation, histones modifications and microRNA) has allowed to consider many new perspectives. Indeed, dysregulation (hyper- or hypomethylation) of many genes has already been highlighted. This method of analysis is the subject of numerous studies in order to develop diagnostic, prognostic and therapeutic tools for this disease which is becoming a real public health problem.