Although endometriosis is a common gynecologic pathologic phenomenon, involvement of the urinary tract is relatively rare. The clinical presentation and course of urinary system disease is extremely variable, as illustrated by the seven cases presented in this report. Therapy primarily is surgical, but a thorough understanding of the disease process and a complete knowledge of the patient's history and desires for fertility conservation are necessary to plot the most appropriate treatment course. Bladder involvement is more common, and usually less devastating, than either ureteral or kidney involvement. No signs, symptoms, or physical findings are pathognomonic, and the clinician must maintain a high index of suspicion in all cases of advanced pelvic endometriosis.