Ban Ki-Moon on Thursday formally offered his resignation as South Korea's foreign minister before taking over as United Nations Secretary-General in January, officials said.
Ban tendered his resignation during a meeting with President Roh Moo-Hyun, presidential spokesman Yoon Tae-Yong said.
He returned from New York earlier on Thursday for talks with US Secretary of State Condoleezza Rice, who is on a tour of Asia and Russia to push for strict enforcement of sanctions against North Korea.
"Ban briefed the president on his last schedule as foreign minister and said he plans to return to New York on November 15 to prepare for his inauguration as UN secretary-general," the spokesman said.
Ban's successor could be named in the middle of next month, Yonhap news agency said, adding that Roh's chief security aide Song Min-Soon and Vice Foreign Minister Yu Myung-Hwan are among the candidates.