Microperforate hymen is a congenital obstructive vaginal membrane with a tiny opening. It is usually detected long before menarche because of recurring vulvovaginitis and urinary tract infection. We report a case of microperforate hymen in a 27-year-old women presenting oligomenorrhea, in whom the location of the tiny opening on the hymenal membrane was detected by withdrawal bleeding without anesthesia, and definitively diagnosed preoperatively by using hysterofiberscopy.