This paper documents two key costs of AD protection. First, once AD has been adopted countries often have a difficult time restraining its use. In recent years 'new' users have accounted for half of the overall world total. Many of the heaviest AD users are countries who did not even have an AD statute a decade ago. Second, I will show that that on average AD duties cause the value of imports to fall by 30-50%. I find that trade falls by almost as much for settled cases as those that result in duties. Interestingly, I also find that even for those cases that are rejected imports fall. The spread and impact of AD protection most surely implies that AD will continue to be a key negotiating item in the next WTO round.