US President Joe Biden's administration will re-engage the UN Human Rights Council.
The move comes three years after former president Donald Trump withdrew over what his administration called bias against Israel and a lack of reform.
Secretary of State Antony Blinken was expected to announce on Monday that the US will return to the Geneva-based council as an observer, a senior State Department official said on Sunday.
"We intend to do so knowing that the most effective way to reform and improve the Council is to engage with it in a principled fashion," the official said.
"We know that the Council has the potential to be an important forum for those fighting tyranny and injustice around the world. By being present at the table, we seek to reform it and ensure it can live up to that potential," the official said.
Mr Trump, a Republican whose "America First" agenda contributed to his decisions to withdraw from a number of international organisations and agreements, pulled the US out of the Human Rights Council in 2018, halfway through its three-year term, over what he called chronic bias against Israel and a lack of reform.
The 193-member UN General Assembly is due to elect new members to the council later this year.
Members are elected for three years and cannot serve more than two consecutive terms.
Candidates are elected by secret ballot in geographical groups to ensure even representation.
The next session of the 47-member Geneva-based council is due to start later this month.
