A medical expert has warned kids who have Heelys to wear elbow pads and helmets to stop them getting hurt.
A doctor at the Royal Victoria Hospital in Belfast said he had treated 11 children since Christmas who had fallen off Heelys and hurt themselves.
Some of the injuries included broken elbows, wrists and legs.
But the company who makes the shoes, which have tiny wheels in their heel, said wheeled shoes had the best safety record of all wheeled sports.
It said you were much more likely to hurt yourself riding a bike.
But a top doctor at the hospital, called Alan McKinney, said broken bones could be prevented if you wear safety gear with your Heelys.
He told the Irish News in Belfast: "Some of the fractures are really nasty and could be easily prevented if elbow pads and helmets were worn."
The shoes, which allow you to switch from walking to wheeling really easily, have been banned in some shopping centres in the UK.
In America a 12-year-old boy died when he fell in front of a car while using the shoes.
Have you ever been hurt wearing Heelys? Email us now using the form on the right-hand-side.
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I tried some Heelys on in a shop to see if I wanted some for my birthday. I tried them on and fell over. I twisted my ankle and badly bruised my knee.
Anna, 12, London
I really wanted Heelys, but my dad told me it was too dangerous, and so he didn't get them for me.
Michelle, 12, Liverpool
I got my Heelys a year ago - I fell over once, but it was my own fault - I was on a rocky slope!
Charlie, 13, Holland