Officials from both sides said final details needed to be worked out for a formal deal to be signed by the countries' top trade negotiators next week in Vietnam.
U.S. President George W. Bush and Russian President Vladimir Putin will meet in Hanoi next week for the Asia-Pacific Economic Cooperation (APEC) summit.
Russia is the largest economy outside the 149-member WTO and has been seeking accession for 13 years. The United States is the last major country whose approval it needs to join the body, which sets global trade rules.
The two countries had attempted but failed to resolve differences in time for the Group of Eight summit in St. Petersburg in July.
(compiled from agency reports)