Endometriosis is described as the presence of endometrial tissue outside the uterine corpus. Though urinary tract endometriosis is uncommon, the bladder is the most common localization amongst them. Here we present three cases admitted to our hospital with similar complaints such as dysuria and abdominal pain. All of the patients had previous cesarean section history. And radiological examination of the bladder revealed solid masses located on the bladder wall. One of the case additionally had a protruding, polipoid luminal mass. Two of the cases were treated with transurethral resection and one with partial cystectomy. We noted similar histological findings such as endometrial stroma and glands within the smooth muscle fibers.  The stromal components were positive with CD10, epithelial components were positive with both estrogen and progesterone receptor immunohistochemically. As a result bladder endometriosis should be kept in mind in the differential diagnosis of mass forming urinary tract  lesions.