The matrix metalloproteinase (MMP) system is composed of the enzymatic component, the MMPs, and the enzyme inhibitory component, the tissue inhibitors of metalloproteinases or TIMPs. It is well established that the MMP system plays a critical role during the normal development and growth of the endometrium as well as many other physiological processes. Because of the necessity for the balance between MMP and TIMP, it is not surprising that aberrant expression of MMPs and TIMPs is associated with the pathophysiology of many diseases. Included in this list is the female disease endometriosis, a disease in which endometrial tissue grows outside of the uterus usually within the pelvic cavity. Both endometriotic (ectopic) endometrial tissue as well as the eutopic endometrium from women with the disease exhibit altered patterns of MMP and TIMP expression which favor tissue invasion/remodeling by the endometriotic tissue. As such, it has been proposed that successful modulation of the MMP system to limit or prevent the invasive events necessary for endometriosis development and/or progression may open new avenues to the medical management of endometriosis. This review will present general knowledge of the MMP system relative to the pathophysiology of the endometriosis as well as address its potential value in relation to the treatment of the disease.