Endometriosis predominantly affects the pelvic reproductive organs, but can also be located outside the reproductive organs as extragenital lesions; the most common sites of extragenital lesions include the intestinal and urinary tracts. Intestinal endometriosis is estimated to affect 3.8-37% of patients with known endometriosis and can manifest as deeply infiltrative lesions of the muscularis or mucosa, or as superficial disease of the serosa or subserosal area. Significant differences in the estimated incidence of intestinal endometriosis may be due to differences in opinion regarding definition, or a reflection of missed diagnosis; a number of women with intestinal endometriosis are diagnosed with other disorders such as irritable bowel syndrome, and may never be appropriately diagnosed with endometriosis. We present the case of a 32 year old nulligravida with rectal stricture due to severe endometriosis, causing constipation and dyschezia. Her medical history is remarkable for a unicornuate uterus with congenital absence of the left kidney and ureter. She underwent low anterior resection of a rectal mass with pathology consistent with endometriosis.