Imperforate hymen is relatively rare but it is the most frequently encountered obstructive anomaly of the female lower genital tract. The clinical presentation vary 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 present with haematocolpos, heamatometra or both. When this happens, the presentation could even be tricky because the patient may presents with unlikely symptoms apart from cryptomenorhoea like, urinary retention or bowel obstruction or both. Here we present a 16 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 hymenotomy and improved dramatically and was discharge 6th day post operatively. This case report is presented to address to clinicians the possibility of imperforate hymen with haematocolpos 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 haematocolpos.