GENEVA, May 21— The World Health Assembly today adopted the first treaty ever devoted entirely to health, one intended to discourage cigarette smoking and to reduce the estimated five million deaths it causes every year.

Health advocates said the next step would be to get the treaty ratified by nations throughout the world. While many countries, including those in the European Union and a number of African nations, said they would quickly sign the treaty, the United States and China -- both large tobacco producers -- made no immediate commitment.

The treaty, called the Framework Convention on Tobacco Control, would ban advertising and sponsorship of television programs and entertainment by tobacco companies. It would impose a warning label that would cover 30 percent of the packaging on smoking products and require that all ingredients be listed on the packaging.

It also urges governments to enact strict indoor air laws, impose high taxes on tobacco and crack down on cigarette smuggling.

''We're thrilled,'' said Cassandra Welch, director of field advocacy for the American Lung Association. ''This is an excellent first step. We have major work ahead of us to concentrate our efforts on ratification.''

The 192 members of the World Health Organization adopted the tobacco treaty by voice vote, after the United States dropped its earlier objections. Today, Tommy G. Thompson, the United States secretary of health, reminded the assembly that America is a world leader in antismoking efforts. ''Together,'' he said, ''we can and will make the global threat of smoking a thing of the past.''

Mr. Thompson refused to say whether the Bush administration would recommend approval of the treaty. ''The United States is carefully reviewing the text of the convention that we adopted today,'' he said. ''We and our outstanding partners worked hard on this treaty.''

The adoption of the treaty was a triumph for the departing director general of the World Health Organization, Gro Harlem Brundtland, who worked for four years to focus attention on smoking as a public health threat. By 2020, the agency estimates, 10 million people will die annually from smoking-related causes, most of them from poor nations.

Dr. Brundtland emphasized in a news conference that today's vote was just a first step. ''A convention on its own doesn't mean much unless the nations that are signatories push it forward,'' she said.

Dr. Brundtland said she was confident of gaining ratification from the minimum 40 nations needed to bring it into force. She added that it was especially important that the United States sign it quickly to send a message to the world.

''The U.S. is a big country and has a lot of influence,'' Dr. Brundtland said. ''A U.S. ratification is important, not only for the people of the United States, but for everyone.''

Before the treaty can take effect in the United States, Congress would have to pass new laws on tobacco use, some of which could be highly contentious. Specifically, Congress would need to ban tobacco advertising where such a prohibition would not conflict with the Constitution and require that warning labels cover at least 30 percent of the package.

Many of these issues had earlier led the United States to seek a way to opt out of certain provisions of the treaty. Its proposals were sharply criticized, however, leading the Bush administration to drop its objections.