Abstract :Acute urinary retention is uncommon in females in general and children in particular. We report a 14-year-old adolescent girl presenting with acute urinary retention due to hematocolpometra secondary to imperforate hymen on a background of chronic constipation. This complicated the delay in diagnosis as there is reluctance of the adolescent girls to allow easy inspection of their external genitalia. Primary amenorrhea in association with cyclical lower abdominal pain and palpable central abdominal lump after relief of the urinary retention and constipation by an enema resulted in ultrasound scan examination which confirmed the diagnosis and perineal examination showed imperforate hymen as the cause. She underwent cruciate interdigiting hymenoplasty uneventfully with excellent cosmetic functional and anatomic results.