Endometriosis is a common gynecologic disease in which endometrial tissue is deposited outside the normal confines of the uterine cavity. In rare instances, endometriosis involves the urinary tract, with the bladder the most frequent organ affected. Classic presenting symptoms include cyclic irritative voiding symptoms and suprapubic discomfort with or without hematuria. Both medical and surgical management have been advocated, but surgical extirpation is probably more efficacious. Two cases of endometriosis involving the the bladder are presented and contrasted in terms of pathophysiology. Contemporary management of this condition is reviewed, and guidelines for diagnosis and treatment are proposed.