Twenty‐three postpartum women underwent perineal ultrasonography to determine bladder neck position at rest, on Valsalva and during pelvic floor contraction. On Valsalva, significant descent of the bladder neck and apposition to the symphysis pubis occurred. During pelvic floor contraction, there was significant elevation of the bladder neck; however, in approximately one‐third of cases no movement was demonstrated. The bladder neck was shown to move through the arc of a circle whose center is the inferior border of the symphysis pubis. Perineal ultrasound provides a simple, objective way of measuring bladder neck elevation during pelvic floor contraction. This may be a more appropriate means of determining treatment outcome, in women undergoing conservative treatment for genuine stress incontinence, than measures of vaginal squeeze pressure. Copyright © 1992 International Society of Ultrasound in Obstetrics and Gynecology