The US government cannot force tobacco firms to put large graphic health warnings on cigarette packages, an appeals court in Washington has ruled.
It said the government's plan undermined free speech in America.
The Food and Drug Administration (FDA) had wanted to put nine pictures of dead and diseased smokers to convey the dangers of cigarettes.
But tobacco firms had argued that the images went beyond factual information and into anti-smoking advocacy.
The ruling comes as a number of other countries have ordered similar pictures to be placed on all cigarette packets.
Australia has gone a step further, banning even tobacco company logos from the cartons.
The US Court of Appeals affirmed an earlier lower court ruling in a 2-1 decision.
It said the case raised "novel questions about the scope of the government's authority to force the manufacturer of a product to go beyond making purely factual and accurate commercial disclosures and undermine its own economic interest".
The court said that in this case it was "by making every single pack of cigarettes in the country a mini billboard for the government's anti-smoking message".
It added that the FDA "has not provided a shred of evidence" that the images would directly advance its policy aimed at reducing the number of smokers in America.
The verdict was welcomed by tobacco companies, with Lorrilard Tobacco's describing it as "a significant vindication of First Amendment principles".
The FDA has so far made no public comment on whether it intends to appeal against the ruling in the US Supreme Court.