Isolated bladder endometriosis is very uncommon. A finding of secondary hydronephrosis has barely been described in the literature. The most common symptom is urethral syndrome and, to a lesser extent, menouria. The most sensitive diagnostic test for bladder endometriosis is cystoscopy. Currently, the most widely used treatment is transurethral resection, with subsequent ovarian suppression with luteinizing hormone-releasing hormone analogues.