The controversial mannequin has a concave stomach with protruding ribs and was on display in Primark's store in Braehead, Glasgow.
The company quickly responded by replacing the window merchandising and stating it would no longer use similar mannequins.
Primark isn't the first retailer to use mannequins to spark discussions about the unhealthy depictions of body shapes in the high street.
Earlier this year lingerie giant La Perla was strongly criticised for using unhealthy-looking mannequins in its New York branch. The store was quick to remove the mannequins, and tweeted that they were updating them, but to what they didn't say.
Images: Primark and La Perla mannequins