Background:
Genital outflow tract obstruction is a common cause of primary amenorrhea. Patients typically present with abdominal/pelvic pain due to hematocolpos and hematosalpinx.

Case:
Two cases are presented here. Fifteen and fourteen-year-old patients complaining of primary amenorrhea and complete transverse vaginal septum on ultrasound. After vaginal septum resection, the patient began menstruating.

Conclusion:
Hematocolpos is a sequel of distal outlet obstruction. Transverse vaginal septum can be seen on ultrasound evaluating its thickness, assessing its level and excluding distal vaginal atresia.