The United States and Russia say they will try to clinch a new strategic arms reduction treaty, Start, by the end of the year.
"This is of the highest priority to our governments," US Secretary of State Hillary Clinton said after talks with her Russian counterpart, Sergei Lavrov.
In turn, Mr Lavrov described the current Start treaty - due to expire at the end of 2009 - as "obsolete".
Mrs Clinton earlier said Washington was keen to "reset" its ties with Moscow to end months of cool relations.
Start 1, which limited the deployment of nuclear warheads to 6000 per side along with 1,600 missiles and bombers, runs out in December this year. It was followed by Start 2, which brought warheads down to 3500.
After the talks in Geneva, Mrs Clinton and Mr Lavrov also said the two sides had agreed to work together on a number of issues of common and world interest, including Afghanistan, the Middle East and North Korea.
The two diplomats admitted that differences in their positions remained. Mrs Clinton said the relationship between the two countries needed "more trust, predictability and progress".
"There are areas where we just flat out disagree and we are not going to paper those over," Mrs Clinton said ahead of the meeting.
"We will not recognise the breakaway areas of Georgia, we do not recognise any sphere of influence on the part of Russia and their having some kind of veto power over who can join the EU or who can join NATO," she added.
Mrs Clinton was also critical of the Bush administration's approach to Russia, saying it was "rather confrontational",
The Secretary of State is is keen to find areas of mutual agreement with countries that have had strained relations with the US, such as Iran, as the new administration looks for help in tackling Afghanistan.
Iran is fighting the importation of narcotics over its border with Afghanistan and Hillary Clinton thinks this problem might encourage Iran to send representatives to an international conference on Afghanistan she is planning for later this month.
