The imaging techniques have a fundamental role in the diagnosis of endometriosis. Ovarian endometriosis (endometrioma) and deep endometriosis can be recognized using transvaginal ultrasound and/or magnetic resonance imaging (MRI). Although transvaginal ultrasound is the first choice of imaging modality when investigating women with pelvic pain, MRI have a role for the wider field of visions. The reproducibility of both techniques has been investigated. The three-dimensional ultrasonography has been proposed. Also studies regarding unusual localizations are reported in the literature. New insights are present about the role of imaging in the detection of the malignant transformations. This review summarizes the current evidence on the diagnostic accuracy of these two techniques in the pre-surgical assessment of endometriosis.