US Special Envoy for Pakistan and Afghanistan James Dobbins met advisor to the Prime Minister on Foreign Affairs and National Security, Sartaj Aziz, in Islamabad on the first day of his visit, Xinhua reported.
They discussed the agenda of talks between Prime Minister Sharif and US President Barack Obama, according to state radio.
Sharif is scheduled to meet Obama at the White House Oct 23.
This will be Sharif's first meeting with President Obama since assuming office in June this year.
US Secretary of State John Kerry had extended a formal invitation to Sharif during the latter's visit to the UN last month.
Dobbins and Aziz also discussed Pakistan-US relations and the situation in Afghanistan and the region, Xinhua cited Radio Pakistan as reporting.
Official sources said both sides focused on the Afghanistan reconciliation process as the end game is fast approaching and US troops will leave by the end of 2014.
They said the two diplomats reviewed the possibility of talks with the Afghan Taliban as the process has been facing a deadlock since the closure of the Taliban office in Qatar in June.
Both countries are now looking at options to revive the Qatar peace process or opting for an alternative path to a political solution prior to the NATO withdrawal.
Taliban supreme leader Mullah Omar Sunday warned that no alternative process other than the Political Office in Qatar will be accepted.
The US is seeking Islamabad's help in the process.
Ambassador Dobbins had also acknowledged recently that Islamabad had increased its support to the Afghan peace process.
He had recognised Pakistan's role in facilitating direct talks between the Afghan government and the Taliban.
"Pakistan has also, particularly over the last six months or so, become active in supporting an Afghan reconciliation process and urging the Afghan Taliban to participate in that process," he had said in September.
Pakistan says it has recently released senior Afghan Taliban leader Mullah Abdul Ghani Baradar to facilitate the peace process. The Taliban, however, say that Mullah Baradar has not yet been freed.