We present the clinical case of a 12-years-old girl with dysuria, abdominal mass in hypogastrium and left iliac fossa. She has not experienced menarche despite a pubertal development in Tanner stage 3. The ultrasound revealed an important retention of blood in the uterus due to imperforate hymen which was resolved by hymenectomy. In cases of dysuria, abdominal mass in adolescent women with no menarche, despite an advanced pubertal development, is important to suspect the imperforate hymen that can be diagnosed in primary care by simple inspection of genitalia. Ultrasound will confirm the suspicions. In doubtful cases magnetic resonance can be used.