The clinical presentation of imperforate hymen varies significantly from patient to patient depending on the age at diagnosis, but in most cases, the diagnosis is missed in early childhood and therefore, the diagnosis is made after puberty when the patient presents with hematocolpos, hematometra or both. When this happens, the patient may present with unlikely symptoms like urinary retention or bowel obstruction or both. Rarely, a neglected case can even present with multiple complications like acute urinary retention and large protruding introital mass with multiple ulcerations, as happened in our case. Here we discuss case of a 15 years old girl with imperforate hymen and presented with history of lower abdominal pain and distension associated with acute urinary retention. She was treated by hymenectomy and improved dramatically and was discharged on the 6th day post operatively. This case report is presented to address the clinicians regarding the possibility of imperforate hymen with hematocolpos as a differential diagnosis in adolescent girls, particularly those who have not started having their menses in their teens and present with acute urinary retention, so that their external genitalia are carefully examined to exclude the possibility of imperforate hymen as a cause of acute urinary retention due to the hematocolpos