President Karzai has ruled Afghanistan since 2001
Afghanistan's President Hamid Karzai has registered as a candidate for the 20 August elections.
He has named Vice-President Karim Khalili and former Vice-President Mohammad Qasim Fahim as running mates.
Mr Karzai said he wanted to run again "to be at the service of the Afghan people" though he had made "some mistakes" during his earlier term.
Mr Karzai has led Afghanistan since 2001 after the fall of the former Taleban regime.
He won Afghanistan's first democratic presidential election in 2004.
Mr Karzai and his two running mates visited the office of the election commission together to register themselves for the elections.
Elections in Afghanistan were due by May, but were postponed to August for security and logistical reasons - a delay that Mr Karzai had earlier challenged.
The commission rejected the president's call for an April vote and set the date for 20 August.
The decision was welcomed by the UN and Nato which said the extra time was needed to improve security.