Colorectal deep infiltrative endometriosis (DIE) can have a major impact on patient’s health and quality of life. Surgical treatment of colorectal DIE varies depending on the location and characteristics of the lesions, which is why the preoperative non-invasive diagnosis needs to be correct and complete. Multiple imaging methods are currently available, but their usefulness is still being studied, as none of them has proven itself perfect. In the present study we wanted to find out to what extent the combined use of magnetic resonance imaging (MRI), endorectal ultrasound (ERUS) and computed tomography-based virtual colonoscopy (CTC) helps perform the preoperative mapping of lesions. We conducted a retrospective study of prospectively collected data that included 49 patients operated for colorectal DIE. In identifying rectal nodules, MRI as a single diagnostic method was the most useful. When ERUS or CTC was added, the concordance between intraoperative and imaging results was very strong. CTC was the most useful in identifying sigmoid nodules. ERUS evaluates the depth of rectal nodules best. CTC assesses best the stenosis for both rectal and sigmoid nodules. Each method contributed to the completion of the diagnosis, so performing ERUS and CTC in addition to MRI seems to be preferable in patients with colorectal DIE.