The presence of functioning endometrium outside uterine mucosa is called endometriosis. It is found in third and fourth decade of life of a female. Clinically patients  present with dysmenorrhea , abnormal uterine bleeding, infertility, dyspareunia, chronic pelvic pain and abdominal pain. Ultrasound is an important tool for diagnosis. I report a rare case of bladder endometriosis, who presented with abdominal pain and heavy menstrual bleeding. On examination a pelvic mass was present which was diagnosed as fibroid with ovarian cyst with the help of USG. So she was planned for surgery. Per op bladder was also involved. So diagnosis of bladder endometriosis was made which was confirmed after histopathological examination.