Laparoscopy and palpation offer only a rough estimate of the extent of endometriosis. Consequently, endometriosis involving the bowels and urinary tract is under-diagnosed. Bowel obstruction and retroperitoneal endometriosis with obstruction of the ureter are uncommon conditions, but awareness of them is important. Ureteric obstruction develops slowly from periureteral fibrosis and often results in an asymptomatic hydronephrosis, loss of renal function and hypertension. Although renography is the first line of choice in investigation of the upper urinary tract in cases of suspected ureteric obstruction, ultrasound of the kidneys may be useful in the hands of the experienced gynecologist as a screening tool at consultation. The rationale for this recommendation is that ureteric obstruction and hydronephrosis often occur simultaneously. We present a case with bowel obstruction mimicking sigmoid carcinoma, ureteric obstruction and hypertension, caused by endometriosis, where the diagnostic difficulties are illustrated. Collaboration between gynecologist and urologist is essential in selected cases of endometriosis.