Modern imaging techniques allow for the noninvasive diagnosis of endometriosis. Preoperative staging of pelvic endometriosis helps the gynecologist plan therapy and offer a prognosis to patients. The challenge of creating a satisfactory classification of endometriosis remains. The ability of the current classification schemes to predict pregnancy outcome, or aid in the management of pelvic pain, is recognized to be inadequate. The study of deeply infiltrating endometriosis and adenomyosis is greatly hampered by a lack of clear terminology and the absence of a consensus classification of the lesions. A reviewed consensus classification of endometriosis in general, with a more detailed consideration on deep endometriosis, is urgently required. We suggest a new staging system for deep, infiltrating endometriosis based on ultrasonographic findings. Prospective data collection and review in large centers may provide a larger clinical base from which to derive empirical point scores and breakpoints in the classification scheme.