It is a widespread assumption that normal micturition behaviour is reflected in a normal flow pattern. This would also mean that a normal flow curve would correspond with normal voiding and would even permit to exclude voiding difficulties. In our study we investigated the value of a normal flow pattern in four different groups: stress incontinent women, women with bladder overactivity, healthy middle-aged volunteers and healthy students. These women voided with a bell-shaped flow curve on pressure flow in 50, 65, 57 and 50%, respectively. Women who strained to void, a major component of dysfunctional voiding, managed to void a bell-shaped flow curve in 46, 60, 70 and 100%, respectively. Our study demonstrates that a "normal" bell-shaped flow curve does not exclude voiding dysfunction in women.