Trade among the former Soviet republics has often seemed chaotic, marred by politics, fraud and strange barter deals, like a swap in the mid-1990s when Ukraine paid for natural gas with a vast quantity of rubber boots instead of cash.

The final hurdle for Ukraine to join the W.T.O. was an agreement to lower existing export tariffs on cattle, animal skins and ferrous metals, and not to raise them in the foreseeable future.

The deal — about three years after Mr. Yushchenko came to power in widespread protests that became known as the Orange Revolution, pledging to integrate Ukraine more closely with the West — paves the way for talks on creating a trade zone with the European Union.

While the European bloc has declined to open membership talks, it kept the door open for discussions on a trade pact if Ukraine became a member of the W.T.O. first.

Newsletter Sign Up Continue reading the main story Please verify you're not a robot by clicking the box. Invalid email address. Please re-enter. You must select a newsletter to subscribe to. Sign Up You will receive emails containing news content , updates and promotions from The New York Times. You may opt-out at any time. You agree to receive occasional updates and special offers for The New York Times's products and services. Thank you for subscribing. An error has occurred. Please try again later. View all New York Times newsletters.

The membership can be expected to give Ukraine some leverage in settling disputes with Russia over steel, sugar and dairy products. Though Russia is working to join the W.T.O., because Ukraine is now in, it will have a veto on Russian membership.

Another Russian neighbor, Georgia, has threatened to use its veto against Russian membership unless Moscow removes customs checkpoints in the separatist territories of Abkhazia and South Ossetia, and lifts a ban on imports of Georgian wine, ostensibly for health reasons though more likely a result of the souring of political relations between the countries. Russia also bans the import of Georgian mineral water and citrus fruit.

Ukraine will take a different tack, Irina Gerashchenko, a member of Parliament from Mr. Yushchenko’s Our Ukraine party, explained in a telephone interview.

Mr. Yushchenko’s support of Russia’s membership, she said, was aimed at ushering Russia into the group as quickly as possible so that Ukraine can avail itself of the W.T.O.’s dispute-resolution mechanisms to settle their conflicts.

Advertisement Continue reading the main story

At the signing ceremony Tuesday, Mr. Yushchenko said that he would support Russia’s membership.

For Ukraine, he said, membership in the W.T.O. would raise the gross domestic product and bring additional billions in foreign investment.

The agreement is subject to ratification by the Ukrainian Parliament, or Rada, by July 4. All major Ukrainian political parties except the Communists support membership, but that may not guarantee easy approval.

Earlier in the day, Mr. Yushchenko canceled a speech equivalent to the State of the Union because opposition members of Parliament occupied the rostrum; others hung posters on the walls protesting the president’s support for joining NATO.

The speaker of Parliament removed the presidential speech from the day’s agenda, and the president’s press service said it would be rescheduled. Mr. Yushchenko then flew to Geneva to sign the trade pact.